Assertion (A): If aluminium atoms replace a few silicon atoms in three the dimensional network of silicon dioxide, the overall structure acquires a negative charge. Reason (R): Aluminium is trivalent while silicon is tetravalent. (i) Both A and R are correct and R is the correct explanation of A. (ii) Both A and R are correct but R is not the correct explanation of A. (iii) Both A and R are not correct (iv) A is not correct but R is correct.
Assertion (A): If aluminium atoms replace a few silicon atoms in three the dimensional network of silicon dioxide, the overall structure acquires a negative charge. Reason (R): Aluminium is trivalent while silicon is tetravalent. (i) Both A and R are correct and R is the correct explanation of A. (ii) Both A and R are correct but R is not the correct explanation of A. (iii) Both A and R are not correct (iv) A is not correct but R is correct.

Correct Option is (i)