Question

(a) Name a sodium compound used for softening hard water.
(b) Which compound of calcium is used for disinfecting drinking water supply ?
(c) Name a metal compound which has detergent properties (cleansing properties).
(d) Name one compound of calcium which is used for removing the colour of a coloured cloth.
(e) State a peculiar (or remarkable) property of plaster of Paris.
(f) Name the substance obtained by the action of chlorine on solid (dry) slaked lime.

Lakhmir Singh Chemistry Class 10

Answer 1

Dear Student,

◆ Answers -

(a) Sodium carbonate (Na2CO3) is used for softening hard water.

(b) Calcium hypochlorite (CaOCl2) is used for disinfecting drinking water supply.

(c) Sodium carbonate (Na2CO3) has detergent properties.

(d) Calcium hypochlorite (CaOCl2) is used for removing the colour of a coloured cloth.

(e) When Plaster of Paris is mixed with water, it becomes absolutely hard after some time.

(f) Calcium hypochlorite (CaOCl2) is obtained by the action of chlorine on dry slaked lime.

Hope that is helpful...

Answer 2

Answer:

In this question,

(a) Sodium carbonate ($Na_{2}CO_{3}$) is used for softening hard water.

(b) Calcium oxychloride ($CaOCl_{2}$) is used for disinfecting drinking water supply.

(c) Sodium carbonate ($Na_{2}CO_{3}$) has detergent properties.

(d) Calcium hypochlorite ($Ca(ClO)_{2}$) is used for removing the colour of a coloured cloth.

(e) When Plaster of Paris is mixed with water, it becomes absolutely hard after some time.

(f) Calcium hypochlorite ($Ca(ClO)_{2}$) is obtained by the action of chlorine on dry slaked lime.

The chemical reaction for the action is as follows –

$2 \mathrm{Cl}_{2}+2 \mathrm{Ca}(\mathrm{OH})_{2} \rightarrow \mathrm{CaOCl}_{2}+\mathrm{CaCl}_{2}+\mathrm{H}_{2} \boldsymbol{O}$