Question

The following can convert hard water into soft water:
(A) $HCl$
(B) ${H_2}{O_7}$
(C) Lead nitrate
(D) Sodium aluminium silicate

Answer 1

We should firstly discuss the hard and the soft water. Further what makes the water hard and what he methods through which it can be softened. Also we will discuss the type of minerals present in the water and what are effects.

Complete step by step solution:
Firstly we need to discuss here that hard water is the water that contains the salts of calcium and magnesium as we have discussed here that hard water contains salts therefore they are not suitable for drinking. Further talking about the soft water we come to know that the soft water is basically the naturally occurring water found as rainfall and in ponds and lakes. not because of the health benefits, but the flavour is very salty. Moreover, it is not that there is no ion in the soft water but it contains sodium ions which are further fit for drinking. Here we can say that the hardness of water can be removed and converted to soft water when the sodium aluminium silicate is added, sodium replaces calcium and magnesium by absorption, hence water becomes soft.
These sodium aluminium silicates are one of the few occurring zeolites. Moreover as we know that the water is crystal clear it contains minerals and chemicals. The concentration of certain minerals is what creates the hardness of water.

Hence, option D is correct.

Note:
We should note here that the hard water does not give good lather with soaps and detergents and soft water gives a good lather. Moreover, washing of hair and skin with hard water contributes to dryness. Further hard water changes the pH of the skin further weakening it as a barrier against harmful bacteria and infections.