Question

Give reasons.
a) In the formation of ammonia, heat is released.
b) Cyanide ion is a polyatomic ion.

Answer 1

(a) $N_2\left(g\right)+3H_2\left(g\right)⟶2N{H}_3\left(g\right)+\Delta H$

Nitrogen combines with hydrogen to form ammonia and some energy is released. This heat is released because formation of ammonia is an exothermic reaction.

(b) Polyatomic ions are the electrically charged species which are composed of more than one atom. $C{N}^{-}$ is the cyanide ion, composed of carbon and nitrogen, Hence it is a polyatomic ion.