Question

Explain the hydrides of nitrogen family under the following points:
(i) Name and formula, (ii) Basic property,
(iii) Reducing property, (iv) Bond angle,
(v) Melting and Boiling point

Answer 1

(i) Name and formula Name Formula
(1) Nitrogen: Ammonia Nitric Acid $N{H}_3$
$HN{O}_3$
(2) Phosphorous: Phosphine $P{H}_3$
(ii) Basic property: Ammonium is a mono basic anhydride that dissolves in water in in form of $N{H}_{4}OH$ (ammonium) hydroxide.
Ammonium hydroxide is a base. Hence, it has a more basic nature. Nitric acid is also a strong mono-basic acid which ionized in water and form of $H_3{O}^{+}$ and $NN{O}_3^{-}$ ions.
Hence, it has also more basic nature. Phosphene combine with halogen acids in gaseous state and forms phosphonium. There phosphonium halides decompoe as soon as possible and reform phospone.
$P{H}_3+HX\to \underset{\text{Phosphonium halide}}{P{H}_{4}X}$ [X = Cl, Br or I]
$P{H}_{4}X\stackrel{H_{2}O}{\to }P{H}_3-H+X$
Hence it has more acidic property due to formation of $H^{+}$ and it has also more basic nature.
Therefore, it is clear that hydrides of Nitrogen and Nitrogen family has more basic nature.
(ii) Reducing property: Ammonia gas is a strong reducing agent. It reduces hot metallic oxides into metals.
Nitric acid is a strong oxidant i.e. reducing agent, as it easily decomposes to produce nascent oxyen.
$2HN{O}_3\to H_{2}O+2N{O}_2+\underset{\text{Nitrogen di-oxide}}{\left[O\right]}$
On passing phosphene gas into the solutions of copper silver and mercury salts metal phosphides are precipitated.
$3CuS{O}_4+2P{H}_3\to C{u}_3{P}_2+3H_{2}S{O}_4$
$3HgN{O}_3+P{H}_3\to A{g}_{3}P+3HN{O}_3$
Hence, it has strong reducing property.
Therefore, from the above reasons and explanation it is clear that hydrogen of nitrogen family have strong reducing property.
(iv) Bond angle Ammonia: (ref. image)
Bond angle is 107.3${}^o$.
(v) Melting and boiling points: Melting point (except for Sb and Bi) and boiling point increase on going down the group from N to B. This is because, electropositive and metallic character increase and hence binding energy of atomic crystal also increases.