Which salt does not produce hardness in water?

Boiling of hard water is helpful in removing the temporary hardness by converting calcium hydrogen carbonate and magnesium hydrogen carbonate to ....

Lime or $CaCl_2$ is added to water to remove which of the following impurities?

Observe the following statements:
$1.$ Heavy water is harmful for the growth of animals.
$2.$ Heavy water reacts with $Al_4C_3$ and forms $\text{deuterated acetylene}$.
$3.$ $BaCl_2 \cdot 2D_2O$ is an example of $\text{interstitial deuterate}$.
The correct statements are:

Permanent hardness in water cannot be cured by

What properties of water make it useful as a solvent? What types of compounds can it $(i)$ dissolve and $(ii)$ hydrolyse?