B S Bisht, R D Madan and, Nelson A Petrie Solutions for Chapter: Water, Exercise 1: Questions

In which of the following substances can there be an increase in weight when they are exposed to air.

1. Sodium chloride

2. Iron

3. Concentrated sulphuric acid

4. Table salt

5. Sodium carbonate crystals

In which of the following substances can there be: decrease in weight

1. Sodium chloride

2. Iron

3. Concentrated sulphuric acid

4. Table salt

5. Sodium carbonate crystals

In which of the following substances can there be: no change in weight when exposed to air?

1. Sodium chloride

2. Iron

3. Concentrated sulphuric acid

4. Table salt

5. Sodium carbonate crystals

Why hard water does not form lather with soap?

What is the disadvantage of hard water?

Can we use hard water for drinking? Give reason.

Complete the equation:

$$\begin{gathered} 2\mathrm{RNa}+{\mathrm{M}}^{2+}\left(\mathrm{aq}\right)\to ......+...... \\ (\mathrm{M}=\mathrm{Mg},\mathrm{Ca}) \end{gathered}$$

Complete the equation:

$$\begin{gathered} {\mathrm{MSO}}_4+{\mathrm{Na}}_2{\mathrm{CO}}_3\leftrightharpoons \_\_\_\_\_\downarrow +\_\_\_\_\_ \\ (\mathrm{M}=\mathrm{Mg},\mathrm{Ca}) \end{gathered}$$