Question

A compound which releases a reddish brown gas on reaction with concentrated sulphuric acid & copper turnings?
A.Ferrous sulphate
B.Ammonium sulphate
C.Copper nitrate
D.Lead carbonate

Answer 1

Hint: We know that Nitrate ion can be easily identified after heating copper turnings with concentrated sulfuric acid. Brown colour with pungent effervescence is monitored which turns blue litmus red.

Complete step by step solution:
We must know that the sulphuric acid to form nitric acid reacts with the nitrate ion. Nitric acid then for the formation of nitric oxide reacts with the copper turnings. Nitric oxide thus, oxidised to nitrogen dioxide.
\[Cu{\text{ }} + {\text{ }}4HN{O_3} \to {\text{ }}Cu{\left( {N{O_3}} \right)_2} + {\text{ }}2N{O_2} + 2{H_2}O\]
Therefore, we can conclude that the $Cu{(N{O_3})_2}$which releases a reddish brown gas on reaction with concentrated sulphuric acid & copper turnings
Additional Information: Copper nitrate \[\left[ {Cu{\text{ }}{{\left( {N{O_3}} \right)}_2}} \right]\] is an inorganic compound that forms a blue crystalline solid structure. Anhydrous copper nitrate forms deep blue-green crystals and sublimes in a vacuum at stable\[150 - 200^\circ C\]. Copper nitrate also occurs as various five different hydrates where the most common one are the “trihydrate” and “hemipentahydrate”. Acetic anhydride in combination with Copper nitrate is an effective reagent for the nitration of different aromatic compounds which are known as the Menke nitration in honor of the Dutch chemist who discovered that metal nitrates are very effective reagents for the process called nitration.

Note: Copper Nitrate is very toxic to the aquatic life and biological diversity of various water bodies. It’s toxicity affects many living entities as well as surfaces of various positions.Copper Nitrate is an inorganic compound that forms a blue crystalline solid.Copper nitrate also occurs as five different hydrates, the most common ones being the hemipentahydrate and trihydrate.