Question

Question 16.
Which of the following phenomena occur, when a small amount of acid is added to water?
(i) Ionisation
(ii) Neutralisation
(iii) Dilution
(iv) Formation

Choose the correct option from the following:
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (ii) and (iv)

Answer 1

(i) When water is added to an acid, their molecules dissociate to form ions.

$\text{HCl}+{\text{H}}_2\text{O}⟶{\text{H}}^{+}+{\text{Cl}}^{-}+{\text{H}}_2\text{O}$
${\text{H}}_2\text{O}+{\text{H}}^{+}⟶\underset{\underset{\text{ion}}{\text{Hydronium}}}{{\text{H}}_3{\text{O}}^{+}}$

(ii) Mixing of an acid with water is called dilution, it results in the decrease in the concentration of ions, ${\text{H}}_3{\text{O}}^{+}$ per unit volume.

Hence, the correct answer is option (c).