Question

Among the following compounds, the number of compounds that do not produce acidic or basic solutions when dissolved in water is:

$\mathrm{NaCl},{\mathrm{BeCl}}_2,{\mathrm{BaCl}}_2,{\mathrm{Li}}_2\mathrm{O},\mathrm{MgO},{\mathrm{CaH}}_2,{\mathrm{CaSO}}_4$

Answer 1

The compounds that do not produce acidic or basic solutions when dissolved in water are:

1.$\mathrm{MgO}$

• When Magnesium oxide reacts with water it will form magnesium hydroxide$\left(\mathrm{Mg}{\left(\mathrm{OH}\right)}_2\right)$ i.e. a weak base.
• The chemical reaction can be depicted as:
• $\mathrm{MgO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2\downarrow$

2. ${\mathrm{CaH}}_2$

• When calcium hydride reacts with water, it will produce calcium hydroxide$\left(\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\right)$ and Hydrogen is liberated.
• The chemical reaction can be depicted as:
• ${\mathrm{CaH}}_2\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Ca}{\left(\mathrm{OH}\right)}_2\downarrow +2{\mathrm{H}}_2\left(\mathrm{g}\right)$

3. ${\mathrm{CaSO}}_4$

• When Calcium sulfate reacts with water, it is poorly dissolved.
• ${\mathrm{CaSO}}_4\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{poorly}\mathrm{soluble}\mathrm{in}\mathrm{water}$

The other compounds such as $\mathrm{NaCl},{\mathrm{BeCl}}_2,{\mathrm{BaCl}}_2,{\mathrm{Li}}_2\mathrm{O}$ produce acidic or basic solutions when dissolved in water.