(a) the ionic end of soap is on the surface of the cluster while the carbon chain is in the interior of the cluster.

(b) ionic end of soap is in the interior of the cluster and the carbon chain is out of the cluster.

(c) both ionic end and carbon chain are in the interior of the cluster

(d) both ionic end and carbon chain are on the exterior of the cluster

Answer: (a) the ionic end of soap is on the surface of the cluster while the carbon chain is in the interior of the cluster.

Reason: These molecules contain a hydrophobic (water-free) component such as fatty acid or a chain of carbon group fatty alcohol. The molecule also contains a hydrophilic (water-soluble) group such as -COONa or a sulfo group. The hydrophobic part adheres to the fiber and particulate matter and the hydrophilic part adheres to the water.