When zeolite (hydrated sodium aluminium silicate) is treated with hard water,the sodium ions are exchanged with:

What is used to soften water by Clark's method?

Which compound is used to remove the temporary hardness of water in Clark's method?

Which of the following is not correct for $D_2O$?

Which of the following can effectively remove all types of hardness of water?

Select the correct statement about water.
$(i)$ Critical temperature of $H_2O$ is less than $NH_3$.
$(ii)$ Standard boiling point of water is $100 \ ^oC$.
$(iii)$ Critical volume of $H_2O$ is less than $NH_3$.