Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

Hydrogen

Short Answer Type

131. Do you expect different products in solution when aluminium (III) chloride and potassium chloride are treated separately with:
(i) normal water (ii) acidifed water and (iii) alkaline water?

163 Views

132.

What is hard and soft water?

173 Views

Long Answer Type

133. What causes the temporary and permanent hardness of water?
Or
Distinguish clearly between temporary hardness and permanent hardness.
Or
What is hardness of water due to? What are its types?

901 Views

Short Answer Type

134.

Why does hard water not form lather with soap?

574 Views

Long Answer Type

135.

What are different methods used for softening of hard water?

194 Views

136. What is ‘demineralised water’ and how can it be obtained?

150 Views

137. Discuss the principle and method of softening of hard water by synthetic ion-exchange resins.
Or
What do you mean by synthetic ion-exchange resins?

Synthetic ion-exchange resins are of two types:
(i) Cation exchange resins. These are either carboxylic acids or sulphonic acids having the general formula, RCOOH or R-SO₃H where R represents the giant hydrocarbon framework. These resins exchange their H⁺ ions with Ca²⁺ and Mg²⁺ ions present in hard water.

(ii) Anion exchange resin. These are substituted ammonium hydrides the general formula.

Now H⁺ ion produced from cation exchange resins and OH^- ions produced from anion exchange resins combine to form water.