Brackish water mostly contains

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T$.: $Na\underline{H} + H_2O \longrightarrow NaOH + H_2 \uparrow$

When $SO_3$ is treated with heavy water,the product is:

Choose the correct statement about various water softening methods.

Which of the following hydrides has the lowest boiling point?

The ratio of the viscosity (in centipoise) of $D_2O$ to that of $H_2O$ at $25^{\circ} C$ is