Question

A water sample contains magnesium bicarbonates. It does not lather with soap. How can we make the water sample useful for cleaning clothes?

• A. Boiling
• B. Cooling
• C. By addition of sodium
• D. By addition of water

Answer 1

The correct option is A

Boiling

It is given that a water sample contains magnesium bicarbonates and it does not lather with soap.

Temporary hardness in water is due to the presence of magnesium and calcium bicarbonates. It can be removed by simple boiling.

Upon boiling hard water, the bicarbonates are converted into precipitates of calcium and magnesium salts which can be filtered out.

So, we will boil the water sample and use it for cleaning clothes as hard water does give lather with soap while soft water does.