P Block Elements

Observe the following species.

(i) $\mathrm{NH}_3$

(ii) $\mathrm{AlCl}_3$

(iii) $\mathrm{SnCl}_4$

(iv) $\mathrm{CO}_2$

(v) $\mathrm{Ag}^{+}$

(vi) $ \mathrm{HSO}_{4}^{-} $

How many of the above species act as Lewis acids?