Question

Give the basicity of

(c) phosphoric acid.

Answer 1

The number of hydronium ions $\left({\mathrm{H}}_3{\mathrm{O}}^{+}\left(aq\right)\right)$ that is produced per molecule of acid in an aqueous solution is known as its basicity.

The Phosphoric acid $\left({\mathrm{H}}_3{\mathrm{PO}}_4\left(aq\right)\right)$ produces three hydronium ions $\left({\mathrm{H}}_3{\mathrm{O}}^{+}\left(aq\right)\right)$ when it gets completely dissociated.

The reaction is as follows:

${\mathrm{H}}_3{\mathrm{PO}}_4\left(aq\right)+3{\mathrm{H}}_2\mathrm{O}\left(l\right)\rightleftharpoons 3{\mathrm{H}}_3{\mathrm{O}}^{+}\left(aq\right)+{{\mathrm{PO}}_4}^{3-}\left(aq\right)$

Therefore, the basicity of Phosphoric acid is $3$.