Question

A compound contains one $\mathrm{Ca}$, two $\mathrm{O}$ and two $\mathrm{H}$ atoms in its molecule.

The compound is

• A. An acid
• B. A base
• C. A salt
• D. None of these

Answer 1

The correct option is B

A base

Explanation for the correct option:

• The compound formed from one $\mathrm{Ca}$, two $\mathrm{O}$ and two $\mathrm{H}$ atoms is Calcium hydroxide and its formula can be given as $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$.
• Calcium hydroxide also called slaked lime is a source of hydroxide ions when dissolved in aqueous solutions, therefore, this compound is a base.
• The dissociation of Calcium hydroxide can be represented as:

$\underset{(\mathrm{Calcium}\mathrm{hydroxide})}{\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)}\to \underset{(\mathrm{Calcium}\mathrm{ion})}{{\mathrm{Ca}}^{2+}\left(\mathrm{aq}\right)}+\underset{(\mathrm{Hydroxide}\mathrm{ion})}{2{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)}$

Hence, option (B) is correct.