Explain how vacancies are introduced in an ionic solid when a cation of higher valence is added as an impurity in it.

Explain ii) Ionic solids are hard and brittle.

What happens when lime is added to hard water? Explain.

Assertion (A) :KCl is more likely to show Schottky defect, while Lil is more likely to show Frenkel defect. Reason(R): Schottky defects is more likely in ionic solids in which cations and anions are of comparable size while Frenkel defect is more likely in which cations and anions have large differences in their ionic sizes.

In crystalline solid, atoms, ions or molecules are held in an orderly array. But some point defect is observed in a crystal, when a vacancy is created by an atom or ion dislocated from its normal position to an interstitial site. What is the defect called?

How do you account for the following observations? a) Though alkaline potassium permanganate and acidic potassium permanganate both are used as oxidants, yet in the manufacture of benzoic acid from toluene we use alcoholic potassium permanganate as an oxidant. Why? Write a balanced redox equation for the reaction. b) When concentrated- sulphuric acid is added to an inorganic mixture containing chloride, we get colourless pungent smelling gas 'HCl', but if the mixture contains bromide, then we get red vapours of bromine. Why?

Explain the following terms with suitable examples (i) cationic detergents (ii) anionic detergents and (iii) non-ionic detergents.

In a crystalline solid, some point defects is observed when a vacancy is created by an ion missing from its normal position . What is the name of the defects?