Test
(a) Ar (b) Ne (c) He (d) Kr Solution: Option (c) is the answer. The least reactive of all known elements are noble gases. Because they each have eight valence electrons, their outer energy levels...
(a) 20 (b) 19 (c) 18 (d) 16 Solution: Option (c) is the answer. Its ion Y2+ will have a total of 20-2= 18 electrons.
(a) 8 (b) 9 (c) 10 (d) 11 Solution: Option (c) is the answer. Because the number of electrons equals the number of protons, X2- will contain 8+2 electrons = 10 electrons.
(a) Lead ion battery (b) Sodium-ion battery (c) Hydrogen ion battery (d) Lithium-ion battery Solution: Option (d) is the answer. A lithium-ion (Li-ion) battery is a high-performance battery that...
(a) Lithium chloride (b) Ammonium chloride (c) Calcium chloride (d) Carbon tetrachloride Solution: Option (d) is the answer. Carbon tetrachloride is a covalent compound that dissolves in...
(a) High melting point (b) Low melting point (c) Occurrence as solid (d) Conduction of electricity in the molten state. Solution: Option (b) is the answer. Because it is created by the gain of...
(a) KCl and HCl (b) HCl and CCl4 (c) CCl4 and NaCl (d) KCl and CCl4 Solution: Option (b) is the answer. Covalent bonding is found in non-ionic substances. Because two atoms share a pair of...
(a) Y3- (b) Y2+ (c) Y2- (d) Y3+ Solution: Option (d) is the answer. Explanation: Because one atom of the element Y contains 20 protons, the number of electrons will be the same. Its ion Y2+ will...
(a) X2- (b) X3+ (c) Y2- (d) X– Solution: Option (c) is the answer. Explanation: An element X has an atomic number of 16 (2,8,6). As a result, it requires two electrons to complete its octet. As a...
(a) 8 only (b) 2 only (c) 8 or 2 (d) 8 or 4 Solution: Option (c) is the answer. Helium is the only noble gas with a valence shell with two electrons. The valence shells of other noble gases have...
(a) Solubility in water (b) Electrical conductivity in solid-state (c) High melting and boiling points (d) Electrical conductivity in molten state Solution: Option (b) is the answer. Because of the...
X: 2,8 Y: 2,8,7 Z: 2,8,2 Which of the following is correct regarding these elements? Solution: (a) X is a metal (b) Y is a metal (c) Z is a non-metal (d) Y is a non-metal and Z is a metal Solution:...
(a) NaCl (b) CCl4 (c) MgCl2 (d) CaCl2 Solution: Option (b) because it is a covalent compound and they don't conduct electricity. The molecule carbon tetrachloride, or CCl4, is symmetrical, with four...
(a) P and R (b) Q and S (c) P and S (d) R and S Solution: Option (c) is the answer because the atomic numbers of the four elements P, Q, R, and S are 6,10, 12, and 17 respectively. P (6= 2,4) and S...
(a) A and D (b) B and C (c) A and C (d) B and D Solution: Option (d) is the answer. Explanation: The atomic numbers of the four elements A, B, C, and D, respectively, are 6, 8, 10, and 12. B (8=...
(a) 17 (b) 18 (c) 19 (d) 20 Solution: Option (b) is the answer. The element Y has an atomic number of 17. As 1 electron is added to its Y–, the total number of electrons in the Y– will be...
(a) 18 (b) 19 (c) 20 (d) 21 Solution: Option (a) is the answer. To achieve a stable electronic state, element X will lose one of its valence electrons, resulting in the formation of a positive...
(e) Why are covalent compounds generally poor conductors of electricity? (d) Because magnesium chloride is an ionic substance, it will conduct electricity. It conducts electricity because it...
(b) How many electrons are there in the valence shell of (i) a magnesium atom, and (ii) a chlorine atom. (c) Show the formation of magnesium chloride from magnesium and chlorine by the transfer of...
(i) ( CH3 )2 CH NH 2 (ii) CH3 ( CH2 )2 NH 2
(e) How is it that ionic compounds in the solid-state do not conduct electricity but they do so when in molten state? Solution: (d) Ionic compounds are often hard because their oppositely charged...
(b) What is the number of outermost electrons in (i) a sodium atom, and (ii) an oxygen atom? (c) Show the formation of Na2O by the transfer of electrons between the combining atoms. Solution: (a)...
X reacts with dilute hydrochloric acid to produce a gas Y which is used in one type of fire-extinguisher. Name the substance X and gas Y. Write a balanced equation for the chemical reaction which...
Water is an example of a neutral substance. The pH level will always be 7. When a drop of the universal indicator is placed to the test tube contacting water, it becomes green, indicating that the...
(a) What is a universal indicator? For what purpose is it used? (b) How does a universal indicator work? (a) The universal indication is a combination of several indicators that give different...
When it changes into curd (yogurt), will its pH value increase or decrease? Why? Fresh milk has a pH of 6, and when it is turned to curd, it creates lactic acid. Because the production is acidic,...
(a) Acids have a pH ______ than 7. (b) Alkalis have a pH _____ than 7. (c) Neutral substances have a pH of _____. (d) The more acidic a solution, the _____ the pH. (e) The more alkaline a solution,...
(e) Why are aqueous solutions of ionic compounds able to conduct electricity? Solution: (d) The solvent in which an ionic substance dissolves is water. Ionic compounds are soluble in water because...
The supplied X and Y imply that an acidic reaction will occur if the pH value is less than 7, hence X is acidic. A pH value greater than 7 implies that the reaction is basic, and hence Y is basic.
Because basic solutions have a pH value greater than 7, Drink Q has a pH value of 9.
Solution A has a pH of 3.0, making it acidic because it is less than 7. As a result, the litmus solution will shift from blue to red, and because solution B is basic (pH 9.5), it will transform...
According to the universal indicator, solution Y is more acidic since it becomes red, indicating a pH of one, whereas orange shows a value greater than one.
When it's exposed to universal indication, it turns red. When the pH drops by seven points, the solution becomes more acidic, and the hydrogen ion concentration rises. As a result, it will be a...
(a) Potassium hydroxide, pH = 12 (b) Soda water, pH = 5 (c) Sulphuric acid, pH = 2 (a) Dark Purple (b) Orange Yellow (c) Red
The pH of a solution is tested using a universal indicator. It changes colour depending on the number of hydrogen ions present. The indicator tells us how powerful or weak an acid or base is.
Because the pH of Soil B is less than 7, it is acidic. As a result, soil B should be treated with powdered chalk to reduce acidity and allow plants to thrive.
The strength or weakness of an acid or base is determined by a universal indicator. It is a combination of a number of different indicators. It has a pH range of 3 to 11, with a pH of 3 being the...
In 1909, a Danish chemist named Soren Sorenson created the pH scale. pH scale was later updated to the contemporary pH scale in 1924.
A pH of more than 7 indicates that the solution is basic. It is evident that a solution with a pH of 11 will be more basic than one with a pH of 8. As the pH of the solution rises, so does the...
The pH has been separated into three levels according to the pH scale. Bases have a pH greater than 7, Acids have a pH of less than 7, When it comes to neutral solutions, pH = 7.0 Hence, a solution...
pH is the potential of hydrogen. For a neutral solution, pH is always 7. Water has a pH of 7.
When the pH of the mouth is less than 5.5, tooth decay begins because the mouth becomes acidic. When the pH is less than 5.5, bacteria in our mouth make acids by breaking down food particles. Enamel...
Because alkali has a unique virtue of being soluble in water, when bases are dissolved in water, hydroxide ions occur. Although not all bases are alkalis, all alkalis are bases.
Alkalis are the common name for water-soluble bases. It is a unique base that dissolves in water with no chemical reaction. It has a pH of greater than 7.
(a) Hydrochloric acid solution (b) Sodium hydroxide solution (a) When zinc granules are treated with hydrochloric acid, zinc chloride produces hydrogen gas. (b) Sodium zincate produces hydrogen gas...
(a) H+ ions interact with OH– ions and are transformed to water during the neutralization reaction. The reaction can be described as follows: (b) The temperature of the solution rises as heat is...
The neutralization of carbonate with an acid differs from the neutralization of oxides with an acid.
One of these test -tubes contain distilled water and the other two contain an acidic and a basic solution respectively. If you are given only blue litmus paper, how will you identify the contents of...
When soap is rubbed on this shirt during washing, the yellow stain turns reddish-brown. On rinsing the shirt with plenty of water, the reddish-brown stain turns yellow again. (a) Name the natural...
(a) Predict the new compound formed which imparts a blue-green colour to solution. (b) Write a balanced chemical equation of the reaction which takes place. (c) On the basis of the above reaction,...
Lemon juice, Vinegar, Baking soda solution? Give reason for your choice. Because baking soda is basic in nature, it neutralizes the excess acid created in the stomach, so it is recommended for the...
(a) What are X, Y, and Z? (b) Write equations for the reactions which take place: (i) when limestone reacts with dilute HCl (ii) when gas X reacts with limewater to form white precipitate Y. (iii)...
(a) Mg(OH)2 (b) Na2CO3 (c) NaCl (d) HCl Option (d) is the answer. When zinc granules react with HCl, hydrogen gas is produced, which burns with a 'pop' sound.
(a) Methyl orange (b) Turmeric paper (c) Phenolphthalein(d) Litmus paper Option (c) is the answer. In an alkaline solution, phenolphthalein turns pink; in an acidic solution, it turns...
(b) How many electrons are there in the valence shell of (i) a magnesium atom, and (ii) an oxygen atom. (c) Show on a diagram the transfer of electrons between the atoms in the formation of MgO....
(e) Name the anode and the cathode used in the electrolytic refining of impure copper metal. Solution: (d) Because sodium chloride is an ionic compound, it has a high melting point. Ionic compounds...
(b) How many electrons are there in the outermost shell of (i) a sodium atom, and (ii) a chlorine atom? (c) Show the formation of NaCl from sodium and chlorine atoms by the transfer of electron(s)....
Solution: Because ions in solid ion compounds are bound together by strong electrostatic forces, their free movement is constrained. When it dissolves or melts in water, the crystal structure...
(a) Have sweet taste (b) Have a bitter taste (c) Are tasteless (d) Have a sour taste Option (d) is the answer. Vinegar and curd are acidic and have a sour taste.
(iii) CaO (iv) N2 (v) CaCl2 Solution: (iii) Ionic bond (iv) (v)
(a) Vinegar (b) Lemon juice (c) Baking soda (d) Caustic soda Option (c) is the answer. Baking soda is a base that neutralizes excess stomach acid and relieves...
(a) Turmeric and litmus (b) Phenolphthalein and methyl orange (c) Litmus and methyl orange (d) Phenolphthalein and litmus Option (c) is the answer. Litmus and methyl orange turn...
(a) They have a sour taste (b) They feel soapy (c) They turn litmus paper (d) Their pH is less than seven Option (b) is the answer. Acids have a sour taste, stain litmus paper red, and have a pH...
(a) Ethanoic acid (b) Formic acid (c) Citric acid (d) Carbonic acid Option (d) is the answer. Carbonic acid is an inorganic or mineral acid that is generated when carbon dioxide is...
(a) Na2SO4 (b) CaSO4 (c) H2SO4 (d) K2SO4 The option (c) is the answer. Marble chips contain calcium carbonate, which combines with sulphuric acid to produce carbon dioxide,...
(a) Antibiotic (b) Analgesic (c) Antacid (d) Antiseptic Option (c) is the answer. Indigestion is caused by an excess of acid in the stomach, and an antacid is a drug that neutralizes...
If we take 20 ml of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralize it will be : (a) 4 ml (b) 8ml (c)12 ml (d) 16ml Option (d)...
(a) Which element is common to all acids? (b) Compounds such as alcohol and glucose also contain hydrogen but are not categorized as acids. Describe an activity to prove it. Answer: (a) Hydrogen is...
Procedure: In a clean, dry test tube, place roughly 1 gram of sodium chloride. Add some concentrated sulphuric acid, and gas will be released through the delivery tube. Test the gas using dry strips...
(i) For a short time? (ii) For a considerable time? Write equations of the reactions involved. Answer: (i) Lime water turns milky when carbon dioxide is injected into it. (ii) Lime water solution...
When an acid combines with a metal carbonate, salt, carbon dioxide, and water are produced. For example, sodium chloride, carbon dioxide, and water are generated when dilute hydrochloric acid...
(a)Why do acids not show acidic behavior in the absence of water? (b)Why does an aqueous solution of acid conduct electricity? (c)Why does distilled water not conduct electricity whereas rainwater...
(i) KCl (ii) NH3 Solution: (i) Because Potassium has an electronegativity of 0.82 and Chlorine has an electronegativity of 3.16, KCl is ionic in nature. The difference in electronegativity of these...
(a) What is produced if an acid is added to a base? (b) Why does dry HCl gas not change the color of dry litmus paper? (c) What color does phenolphthalein indicator turn when added to an alkali...
Curds and other sour foods are naturally acidic. Acids react with the metal to produce hydrogen gas, spoiling the meal and forming toxic metal compounds, making the food dangerous.
The neutralization process occurs when an acid reacts with a base, resulting in the creation of salt and water. Sodium chloride and water are generated when sodium hydroxide and hydrochloric acid...
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Acidic properties are determined by the dissociation of HCl, H2SO4, and HNO3 in aqueous solutions to yield H+ ions. Despite the presence of hydrogen atoms, glucose and alcohol do not separate in an...
Solution: The outermost electron shell of an oxygen atom contains 6 electrons, and it requires 2 additional electrons to complete its octet. As a result, it joins with another oxygen atom to form an...
(iii) H2O (iv) HCl (v) MgCl2 (iii) Covalent bond: A chemical bond between two non-metal atoms is known as a covalent bond. Water, for example, is made up of hydrogen (H) and oxygen (O) bonded...
Classify the following into strong acids and weak acids : HCl, CH3COOH, H2SO4, HNO3, H2CO3, H2SO3 Answer: A strong acid forms a considerable amount of hydrogen ions when it totally ionizes in water....
(a) What are organic acids and mineral acids? (b) Give two examples each of organic acids and mineral acids. (c) State some of the uses of mineral acids in industry. Answer: (a) Organic acids...
When an acid reacts with metal oxide, salt and water are obtained. The reaction can be written as follows, Acid+ Metal oxide → Salt + water When a small amount of copper oxide is added to sulphuric...
(i) CO2 (ii) MgO Solution: (i) Covalent bond Carbon dioxide is a three-atom covalent molecule, with carbon surrounded by two oxygen atoms. Each carbon-oxygen bond has a bond order of two. There are...
When an acid reacts with a base salt and water are produced. When hydrochloric acid combines with sodium hydroxide solution, sodium chloride and water are formed as a result of a neutralization...
(a) What happens when dilute hydrochloric acid is added to sodium carbonate? Write the balanced equation of the reaction involved. (b) Which gas is liberated when diluting hydrochloric acid reacts...
Carbon dioxide gas is released with a metal salt and water when an acid is applied to metal hydrogen carbonate. When sodium hydrogen carbonate reacts with hydrochloric acid, sodium chloride and...
Solution: Nitrogen has 5 electrons in its outermost shell; it requires 3 more electrons to complete the octet, so it joins with another nitrogen atom to form a molecule of nitrogen gas.
When diluting an acid, it should always be done slowly and in little amounts, with steady stirring. An acid dilution is an exothermic reaction. When we add acid to water, the heat that is generated...
(a)What happens when an acid reacts with a metal? Give the chemical equation of the reaction involved. (b) Which gas is usually liberated when an acid reacts with a metal? How will you test for the...
Solution: Cations are positively charged ions that are produced when an atom loses one or more of its electrons. Consider the following example: To generate the sodium ion Na+, sodium loses one...
Solution: Sodium has an atomic number of 11 and an electrical configuration of 2,8,1. In its valence shell, it has one electron. Chlorine has an atomic number of 17 and an electrical configuration...
(i) Calcium and Oxygen (ii) Carbon and Chlorine (iii) Hydrogen and Chlorine. Solution: (i) Calcium and oxygen have ionic bonding because calcium loses two electrons and oxygen obtains one to...
(i) Which inert gas does the H atom in HCl resemble in electron arrangement? (ii) Which inert gas does the Cl atom in HCl resemble in electron arrangement? Solution: (i) Helium atom is the inert gas...
(ii)Show the formation of MgO by the transfer of electrons. (iii)What are the ions present in this compound? Solution: (i) (ii) (iii) Both positive and negative ions are present. Mg2+ and...
(b)What is the cause of chemical bonding (or chemical combination) of atoms of elements? Solution: (a) Noble gases, also known as inert gases, are gases that do not react with other elements and...
(c) Al and Cl2 (d) K and H Solution: (c) AlCl3 (d) KH (c) Al and Cl2 react to form AlCl3 (aluminium chloride). (d) K and H react to form KH (potassium hydride).
(a) Mg and N2 (b) Li and O2 Solution: (a) Mg3N2 (b) Li2O A formula is a representation of a compound using symbols for each of its constituent parts. (a) Mg interacts with N2 to generate Mg3N2...
Solution: Because common salt is an ionic compound, it is made up of charged ions, but sugar cane is a covalent compound, it is made up of electrically neutral molecules and hence does not conduct...
(b) How will you find out which of the water-soluble compound A or B is ionic? Solution: Sodium chloride, NaCl, is an ionic substance. Both atoms possess appreciable differences in charge. Carbon...
(b) Which of the following will conduct electricity and which not? MgCl2, CCl4, NaCl, CS2, Na2S Solution: (a) Ionic compounds contain electrically charged ions and conduct electricity, whereas...
(b) State one test by which sodium chloride can be distinguished from sugar. Solution; (a)(i) Ionic chemicals are water-soluble. Their melting and boiling points are both very high. (ii) Covalent...
(a)Covalent compounds have generally low melting points. (b)Ionic compounds have generally high melting points. Solution: (a) Because covalent compounds are made up of electrically neutral...
(b) Compare the properties of ionic compounds and covalent compounds. Solution: (a) (i)Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely...
(b)Explain the formation of a chlorine molecule on the basis of the electron theory of valency. Solution: (a) The covalent bond is present in the chlorine molecule because a covalent bond is...
(b)What is the nature of charge on (i) a cation, and (ii) an anion? (c)Name the cation and anion present in MgCl2. Also, write their symbols. Solution: (a) Ions are electrically charged particles....
Solution: The electrostatic attraction between oppositely charged ions in a chemical molecule forms an ionic bond, also known as an electrovalent bond. When the valence (outermost) electrons of one...
Solution: (a) A chemical bond involving the sharing of electron pairs between atoms is known as a covalent bond. Shared pairs or bonding pairs are the stable balance of attractive and repulsive...
(v) The number of single covalent bonds in C2H2 molecule are _____. (vi) Melting points and boiling points of ionic compounds are generally _____ than those of covalent compounds. Solution: (v) Two:...
(iii) In forming an oxygen molecule, _____ electrons are shared by each atom of oxygen. (iv) In forming an N2 molecule, _____ electrons are shared by each atom of nitrogen. Solution: (iii) Two,...
(i)Two atoms of the same element combine to form a molecule. The bond between them is known as _ bond. (ii) Two chlorine atoms combine to form a molecule. The bond between them is known as _....
(a) An alkali metal in period 3 and halogen in period 2 (b) The noble gas with 3 shells (c) The non-metals present in period 2 and metals in period 3. (d) The element of period 3...
(iii)A molecule containing a triple covalent bond (iv)A compound containing an ionic bond Solution: (iii) Nitrogen is the only chemical with three covalent bonds.The chemical sector relies on...
(i)A molecule containing a single covalent bond (ii)A molecule containing a double covalent bond Solution: (i) The molecule with a single covalent link is hydrogen. The chemical element hydrogen has...
Urea, Cane sugar, Hydrogen chloride, Sodium chloride, Ammonium chloride, Carbon tetrachloride, Ammonia, alcohol, Magnesium chloride. Solution: Ionic compounds: Sodium Chloride, Ammonium chloride and...
Solution: The electron configuration of the Cl atoms in Cl2 is Argon, which is an inert gas. It has a 2, 8, 8 electronic configuration.
(iii) Cl2 (iv) O2 Solution: Covalent bonds are present in the given molecules. (iii) Cl2 : An electron pair is shared by the two atoms of chlorine (Cl2). Covalent bonding is the term for this. Atoms...
(i) H2 (ii) CH4 Solution: The given compounds include covalent bonds. (i) H2 : The hydrogen molecule is the most basic covalently bound material. It is made up of two hydrogen atoms, each of which...
Solution: When dissolved in water or melted, ionic compounds are good conductors of electricity, but covalent compounds do not. The melting and boiling points of covalent compounds are frequently...
Solution: Covalent bonds exist in methane, while ionic bonds exist in sodium chloride. The four strong C–H carbon-hydrogen covalent bonds hold the methane molecule together by sharing electrons.The...
Solution: A water molecule is made up of two hydrogen atoms bonded by covalent bonds to the same oxygen atom. Because oxygen atoms are electronegative, the shared electrons in their covalent bonds...
(i) NaCl (ii) Cl2 Solution: (i) Sodium chloride, commonly known as salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses...
Solution: In hydrogen chloride, the chemical link is a covalent bond. One electron from each of the hydrogen and chlorine atoms is shared between the two atoms in hydrogen chloride. An oxygen...
The aqueous solution of an ionic compound conducts electricity because there are plenty of free electrons in the solution. Solution: The claim is untrue. Because there are a lot of free ‘ions' in an...
Solution: Ionic bonds exist in a solid compound with a high melting point that does not conduct electricity in its solid form but does so in its molten state. Ionic bonding is the principal...
(b)Write down the electronic configuration of (i) sulphur atom, and (ii) sulphide ion, (At. No. of S = 16) Solution: (a) (i) Mg = 2, 8, 2 (ii) Mg2+ = 2, 8 (b) (i) S = 2, 8, 6 (ii) S2- = 2,...
Solution: X will form X2- as its atomic number is 8 (2,6). It needs 2 more electrons to fulfil its octet rule. Y will form Y2+ as its atomic number is 12 (2,6,2). It needs to remove 2 electrons to...
When it's combined in an acidic or basic solution, olfactory markers are the smells or odors that alter. It can be used in the lab to determine whether a solution is acid or basic, as well as to do...
(a) What is an indicator? Name three common indicators. (b) Name the acid-base indicator extracted from lichen. (c) What color does the turmeric paper turn when put in an alkaline solution? Answer:...
(a) Acids produce _______ ions on dissolving in water. (b) Those substances whose smell (or odour) changes in acidic or basic solutions are called _______ indicators. (c) Onion and vanilla extract...
(a) Acids have a _______ taste and they turn _______ litmus to _______. (b) Substances do not show their acidic properties without _______. Answer: (a) Sour; blue; bed. (b) Water. (c)...
(a) NaOH(aq) + HCl(aq) → (b) CuO(s) + HCl (aq) → Answer: (a) (b)
(a) Zn(s) + HCl(aq) → (b) Na2CO3(s) + HCl (aq) → (c) NaHCO3(s) + 6 HCl → Answer:
ac) dilute sulphuric acid reacts with ammonium powder. (b) dilute hydrochloric acid reacts with iron filings. Answer: (a) (b)
(a) dilute sulphuric acid reacts with zinc granules. (b) dilute hydrochloric acid reacts with magnesium ribbon. Answer:
When an acid is diluted, the concentration of hydronium ion falls. As a result, the acid's strength falls. The volume of solute (acid)/Volume of solution = Concentration of hydronium ions
Ants have stings that include formic acid. Nettle leaf sting is a plant sting that contains formic acid.
(a) Lactic acid (b) Tartaric acid Answer: (a) The natural source of Lactic acid is sour milk or curd. (b) The natural source of Tartaric acid is tamarind
(a) Citric acid (b) Oxalic acid Answer: (a) The natural source of citric acid is from Lemon (b) The natural source of oxalic acid is tomatoes
Strong acids breakdown into ions when they come into contact with water. Hydrochloric acid (HCl) and sulphuric acid, for example (H2SO4) The citric acid (C6H8O7) and acetic acid (CH3COOH) are weak...
When hydrochloric acid combines with sodium hydrogen carbonate, carbon dioxide gas is produced. The gas released will flow through lime water, which will turn milky due to the presence of carbon...
When hydrochloric acid reacts with an active metal, hydrogen gas is created at the metal's surface in the form of bubbles, and this gas is transferred via soap, bringing the candle close to the...
The supplied solution will be base since adding a basic solution to vanilla entirely eliminates the vanilla's unique smell, whilst adding an acidic solution has no effect.
Because onion extract loses its scent when mixed with a base, but not when mixed with acid, the suggested solution comprises a base.
(b) The atomic number of chlorine is 17. What is the number of electrons in Cl-? Solution: (a) No. of electrons in Na+= 10 (Since the atomic number of sodium is 11, Na+ will have one less electron.)...
In acid-base titrations, phenolphthalein is employed as an indicator, turning colourless in acidic solutions and pink in basic solutions.
(b) What do we call those particles which have more electrons than the normal atoms? (c) What do we call those particles which have fewer electrons than the normal atoms? Solution: (a) Ions are...
By changing color from solution to solution, litmus is used as an indicator to determine whether a solution is acidic or basic. The color of litmus changes from blue to red in acidic solutions and...
(a) Potassium and bromine? (b) Carbon and bromine? Solution: (a) Ionic bond is the bond between potassium and bromine (b) Covalent bond is the bond between carbon and bromine Explanation: (a)...
(a) Litmus (b) methyl orange Answer: (a) The indicator litmus paper is used to determine whether a solution is acidic or basic. When this is immersed in an acidic solution such as hydrochloric acid,...
Solution: Carbon dioxide is a three-atom covalent molecule, with carbon surrounded by two oxygen atoms. Carbon and oxygen both have p orbitals that can interact due to their symmetry compatibility....
(a) Methyl orange (b) litmus (c) red cabbage extract (a) When methyl orange is mixed with a base, the colour changes to yellow. (b) When litmus paper is dipped in a base solution, it becomes blue....
Solution: Carbon dioxide is a molecule that has two double bonds. Carbon dioxide is an acidic, colourless gas with a density that is roughly 53% that of dry air. A carbon atom is covalently doubly...
(a) By the sharing of electrons between two atoms? (b) By the transfer of electrons from one atom to another? Solution: (a) Covalent bond is the bond formed by sharing of electrons between two atoms...
(a) MgSO4 + Fe (b) ZnSO4 + Fe (c) MgSO4 + Pb (d) CuSO4 + Fe Solution: Option (d) is the answer. Iron displaces copper from its sulphate solution to produce iron sulphate and...
(a) Carbon (b) Sulphur (c) Bromine (d) Iodine Solution: Option (c) is the answer. Bromine is a common element with a unique property: it is the only nonmetal that can exist in liquid form at normal...
(a) Na (b) Ag (c) Cr (d) Hg Solution: Option (d) is the answer. Mercury is a poor heat conductor yet a good electrical conductor. Mercury has a peculiar electron arrangement that makes it behave...
(a) Mg (b) S (c) P (d) Na Solution: Option (d) is the answer. Sodium is so soft that a knife can be used to cut it. When left open in the air, it reacts violently with oxygen, thus we keep it...
(a) Zn (b) Ag (c) Cu (d) Mg Solution: Option (b) is the answer. Because Ag is less reactive than Mg, Zn, and Cu, it would be displaced from the solution of its salts by the other three...
(a) Calcium (b) Carbon (c) Silicon (d) Iron Solution: Option (a) is the answer. Detailed explanation: Calcium combines with oxygen to form calcium oxide, an ionic molecule with a high melting point....
(a) S (b) Ca (c) C (d) Ag Solution: Option (b) is the answer. Calcium is a metal that reacts with water to generate calcium hydroxide, a basic compound found in nature. As a result, the...
(a) Aluminium and lead (b) Iron and magnesium (c) Copper and tin (d) Copper and mercury Solution: Option (c) is the answer. The reactivity series aids in the prediction of metal reactions. The more...
(a) An acidic oxide (b) A basic oxide (c) An amphoteric oxide (d) A neutral oxide Solution: Option (c) is the answer. Explanation: Amphoteric oxides, such as zinc oxide, are metal oxides that have...
(a) Lithium and sodium (b) Copper and potassium (c) Carbon and hydrogen (d) Phosphorus and sulphur Solution: Option (d) is the answer. Explanation: Phosphorus and sulphur are non-metallic oxides...
(a) Carbon and sulphur (b) Sodium and carbon (c) Potassium and magnesium (d) Magnesium and sulphur Solution: Option (c) is the answer. Explanation: Metallic oxides such as potassium and magnesium...
(a) Sulphur (b) Carbon (c) Calcium (d) Hydrogen Solution: Option (b) is the answer. CO2 becomes carbonic acid when it reacts with water, making it acidic in nature. CO is a neutral gas because it...
(a) Sodium and aluminium (b) Zinc and potassium (c) Calcium and sodium (d) Aluminium and zinc Solution: Option (d) is the answer. Both acids and bases react with 'Al' and 'Zn.' As a result, they're...
(a) Fe2O3 (b) Al2O3 (c) P2O5 (d) N2O Solution: Option (b) is the answer. Acids and bases react with aluminium. As a result, it is amphoteric. Amphoteric oxide is the oxide of an amphoteric element....
(a) Carbon (b) Sulphur (c) Chlorine (d) Phosphorus Solution: Option (b) is the answer. Sulphur reacts with hydrogen to produce hydrogen sulphide (H2S), which has a rotten egg odour.
(a) Sodium (b) Silver (c) copper (d) Lead Solution: Option (b) is the answer. Silver is positioned below sodium, copper, and lead in the reactivity sequence. As a result, silver is the least...
(a) Aluminium (b) Copper (c) Tin (d) Calcium Solution: Option (d) is the answer. The reactivity of the above metals is in the following order: Ca>Al>Sn>Cu. The most reactive metal is...
(a) Magnesium (b) Zinc (c) Gold (d) Copper Solution: Option (c) is the answer. According to the reactivity series, magnesium, zinc, and copper seem to be the most reactive metals compared to silver,...
(a) Na (b) C (c) Ca (d) H Solution: Option (b) is the answer. The only non-metal on the list is carbon (C). Non-metals generate acidic oxides when they react with oxygen, while metals form basic...
(a) K (b) S (c) P (d) Kr Solution: Option (a) is the answer. It is empirically known that metals form basic oxides, i.e. metallic oxides are basic in nature. All of the metal elements in the...
(a) CO (b) H2O (c) N2O (d) Na2O Solution: Option (d) is the answer. Na2O is a metal oxide that is basic in nature.
(a) A metal (b) A compound (c) A non-metal (d) A solution Solution: Option (a) is the answer. Metals are malleable and ductile.
(a) Na and K (b) K and C (c) Na and S (d) K and P Solution: Option (a) is the answer. Phenolphthalein is a synthetic indicator that remains colourless in acidic and neutral environments but turns...
Solution: (c) Sodium exists in solid form. It is a conductor of electricity and a source of basic oxides. As a result, sodium is classified as a metal. (d) Sulphur is a hard, brittle substance. It...
Solution: (a) Differences in physical properties between metals and non-metals 1. Metals are malleable, whereas nonmetallic materials are not. 2. Non-metals are non-ductile, whereas metals are...
(d) Name one metal that displaces copper from copper sulphate solution and one which does not. (e) Name one metal that displaces silver from silver nitrate solution and one which does not....
Solution: (a) A reactivity series is a vertical column of items arranged in decreasing order of their reactivities. Increasing order of reactivity : Iron< Zinc< Magnesium< Sodium (b)...
(e) Acidic or neutral oxides are formed when non-metals react with oxygen. Carbon dioxide is produced when carbon is burned in the air. C(s) + O2(g) → CO2(g) The resulting product is acidic....
(c) Iodine has a lustrous sheen to it. Iodine is a chemical element with atomic number 53 and the symbol I. (d) Carbon allotrope diamonds are extremely hard. Carbon is a chemical element with the...
Solution: (a) Non-metals are materials that conduct electricity poorly and are neither malleable nor ductile. Carbon, sulphur, phosphorus, silicon, and oxygen are some examples. (b) Carbon is a good...
Identification: Ore A - Carbonate ore Steps to convert carbonate ore into metal: 1. Calcination - Metal oxide is obtained by heating the ore in the presence of oxygen. Reaction Involved: ACO3→ AO+...
Identification: A - Sodium B - Chlorine C - Sodium Chloride D - Sodium hydroxide Reactions Involved: 2Na +CL2 →2NaCl 2NaCl+ 2H2O→ 2NaOH+ Cl2+H2
Identification: X - Sodium Y - Magnesium Z – Iron Reactions Involved: Na + H₂O → 2NaOH + H₂ Mg + H₂O → Mg(OH)₂ + H₂ Fe + H₂O → Fe₂O₃+ H₂ Arrangement of the metals in order of...
(a) Roasting of copper (1) sulphide (b) Reduction of copper (1) oxide with copper (1) sulphide. (c) Electrolytic refining (ii) Draw a neat and well-labelled diagram for electrolytic refining of...
(a) Reactivity of Al decreases if it is dipped in HNO3 (b) Carbon cannot reduce the oxides of Na or Mg (c) NaCl is not a conductor of electricity in the solid-state whereas it does conduct...
The steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores are heating the ores in the presence of oxygen to produce the oxides of the metal....
(a) Identify A, B, C and D (b) To which group of periodic table does this non-metal belong? Answers: (a) A - Nitrogen Explanation: Nitrogen is the non-metal which is the largest constituent of...
FeSO4 is produced when iron displaces the copper which makes the reactivity of iron higher than that of copper. And this nature of iron is responsible for the holes in the pot. Reaction Involved:...
Identification of the element A is a non-metal as they their oxides are usually acidic.
A - Sodium B - Sodium Hydroxide C - Sodium Aluminate Reaction Involved: Al2O3 +2NaOH →2NaAlO2+H2O
Identification: Metal M - Copper Black colored product - copper oxide Reaction Involved: 2Cu+ O2 →2CuO
Reactions involved during the extraction of zinc from its ore by, (a) Roasting of zinc ore: 2ZnS + 3O2→2ZnO + 2SO2. (b) Calcination of zinc ore: ZnCo3→ZnO+CO
A - Calcium B - Calcium Hydroxide C - Calcium Oxide Reactions Involved: Ca+2H2O →Ca(OH)2+ H2 Ca(OH)2 →CaO+H2O CaO+H2O→ Ca(OH)2
Mercury and Bromine exists in a liquid state at room temperature; Caesium and Gallium has a melting point less than 310 K (37°C).
Examples of good conductors are Iron and Copper. Examples of bad conductors are Lead and Mercury.
(a) Identify A, B and C (b) To which Group of Periodic Table does A belong? Answers: (a) A - Carbon B - Carbon monoxide C - Carbon-dioxide (b) Group...
(a) ZnCO3 is heated in the absence of oxygen? (b) a mixture of Cu2O and Cu2S is heated? Answers: (a) Carbon-di-oxide are liberated Reaction: ZnCo3 →ZnO + CO2 (b) Pure Copper is obtained...