Question

Temporary hardness of water can be removed by :

• A. boiling
• B. saponification
• C. clark's method
• D. chlorination

Answer 1

Answer: (A), (C)

The temporary hardness of water can be removed by boiling. $Ca(HC{O}_3{)}_2\stackrel{boil}{\to }CaC{O}_3\downarrow +C{O}_2\uparrow +H_{2}O$.

Clark's method which uses lime (calcium hydroxide), it is also used for removal of temporary hardness of water.

$Ca(HC{O}_3{)}_2+Ca(OH{)}_2\to 2CaC{O}_3+2H_{2}O$.