Arrange the following ions in the correct order of their acidity: $(i) \, HCO_3^-, (ii) \, H_3O^+, (iii) \, HSO_4^-, (iv) \, HSO_3F$.

Write the characteristics and uses of the $K_{a}$ value.

Give the conjugate acid of the following species: $HS^{-}, NH_{3}, C_{6}H_{5}COO^{-}, OH^{-}$

When a strong acid,strong base,or their salt are dissolved in water,they are completely ionised. If a strong acid is added to a strong base,$H^{+}$ ions from the former combine with $OH^{-}$ ions of the latter forming water. The formation of each water molecule liberates a certain quantity of energy and the reaction is exothermic. The heat liberated when one mole of water is formed by combining hydrochloric acid and sodium hydroxide is $13.7 \, kcal$. The heat liberated when one mole of water is formed by combining sulphuric acid and sodium hydroxide is......$kcal$

In the reaction $NH_3 + H_2O \rightleftharpoons NH_4^+ + OH^-$,water acts as a .......

Match the following species with their respective conjugate acids:

Species	Conjugate acid
$ (a) NH_{3} $	$ (i) H_{2}CO_{3} $
$ (b) HCO_{3}^{-} $	$ (ii) H_{3}O^{+} $
$ (c) H_{2}O $	$ (iii) NH_{4}^{+} $
$ (d) HSO_{4}^{-} $	$ (iv) H_{2}SO_{4} $