Question

What happens if we treat the following compound with hot and concentrated nitric acid?
1. ${{P}_{4}}$
2. $A{{S}_{4}}$

Answer 1

Hint : We know that the diluted nitric acid has no reaction on non-metal and since the carbon is non-metal there is no action of dilute nitric acid on it. But the concentrated nitric acid oxidizes non-metal such as carbon, sulfur to their corresponding oxyacids, and nitric acid itself is reduced to nitrogen dioxide.

Complete Step By Step Answer:
Nitric acid is highly corrosive in nature, if inhaled it irritates and burns the lungs throat badly, which can lead to pulmonary edema and death. Breathing nitric acid may cause death and it burns the skin in contact. Also, being a monobasic acid, it reacts with metallic oxides, hydroxides, carbonates, and bicarbonates and gives salt known as nitrate. Aqua regia is formed using one part of concentrated nitric acid and three parts of concentrated nitric acid and it is known to dissolve almost insoluble substances such as platinum and gold.
-Arsenic forms oxyacids on treatment with hot concentrated nitric acid.
$A{{s}_{4}}+20HN{{O}_{3}}\to 4{{H}_{3}}As{{O}_{4}}+20N{{O}_{2}}+4{{H}_{2}}O.$
-Phosphorus forms oxyacids on treatment with hot concentrated nitric acid.
${{P}_{4}}+20HN{{O}_{3}}\to 20N{{O}_{2}}+4{{H}_{3}}P{{O}_{4}}+4{{H}_{2}}O.$
Phosphorus has a very strong affinity towards oxygen that’s why Phosphorus always tries to bind with Oxygen. Also, Phosphor is a strong reducing agent which gets self-oxidized. And generally, tries to achieve the $+3$ or the $\,+5$ oxidation state. Similarly, Arsenic proceeds in the reaction.

Additional Information:
The purification of gold and silver, manufacture of artificial silk, perfumes and in dyeing and printing. Nitric acid is highly corrosive in nature and is a toxic, colorless, and fuming liquid. It finds its application as an important industrial chemical in the manufacture of explosives and fertilizers.

Note :
Remember that the aqua fortis is a highly corrosive mineral acid. The pure compound is colorless, but older samples tend to acquire a yellow cast due to decomposition. It is a white crystalline solid. It is a dehydrating agent and is used as a strong drying and dehydrating agent.