Which of the following is a good scientific method to detect the presence of water in a liquid?

When temporary hard water containing $Mg(HCO_3)_2$ is boiled,the precipitate formed is of:

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

Statements about heavy water are given below.
$A.$ Heavy water is used in exchange reactions for the study of reaction mechanisms.
$B.$ Heavy water is prepared by exhaustive electrolysis of water.
$C.$ Heavy water has higher boiling point than ordinary water.
$D.$ Viscosity of $H_2O$ is greater than $D_2O$.

What is meant by 'demineralised' water and how can it be obtained?

The maximum number of hydrogen bonds formed by a water molecule in ice is