Question

When copper is heated with concentrated $HN{O_3}$ it produces:
A. \[Cu{(N{O_3})_2}\] and \[N{O_2}\]
B. \[Cu{(N{O_3})_2}\] and \[NO\]
C. \[Cu{(N{O_3})_2}\] , \[NO\] and \[N{O_2}\]
D. \[Cu{(N{O_3})_2}\] and \[{N_2}O\]

Answer 1

Hint: When copper reacts with nitric acid, cupric nitrate is formed with a poisonous reddish brown gas with an irritating pungent odour. We can find out what we have got by observing it.

Complete answer:
Let’s learn about copper and concentrated $HN{O_3}$ before moving on to the question.
Copper is a chemical element with the symbol $Cu$ and atomic number 29. It is a soft, malleable and ductile metal with high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange colour. It is used as a conductor of heat and electricity, as a building material and also as a constituent of various metal alloys. It is one of the few metals that can occur in nature in a directly usable form. It is also essential in all living organisms as a trace dietary mineral because it is a key constituent of the respiratory enzymes.
$HN{O_3}$ is also known as Nitric acid or aqua fortis or spirit of niter. It is a highly corrosive mineral acid. It is colourless in pure form but older samples acquire a yellow cast due to decomposition into oxides of nitrogen and water. It is also referred to as fuming nitric acid. It is a primary reagent used for nitration. It is commonly used as a strong oxidizing agent.
Talking about the reaction between copper and nitric acid, copper is oxidized by concentrated nitric acid to produce \[C{u^{2 + }}\] ions. The nitric acid is reduced to form nitrogen dioxide which is a poisonous brown gas with an irritating odour. Also, Cupric nitrate, \[Cu{(N{O_3})_2}\] is formed in this reaction.
The equation is as given below,
\[Cu + 4HN{O_3} \to Cu{(N{O_3})_2} + 2N{O_2} + 2{H_2}O\]

Hence, the correct answer is option A.

Note: Cupric acid is an inorganic compound that forms a blue crystalline solid. Anhydrous copper nitrate forms deep blue green crystals and sublimes in vacuum. It also occurs as five different hydrates. Main application of copper nitrate is to convert into copper oxide which is used as a catalyst in a variety of processes.