Question

A gas $(X)$ is obtained when copper reacts with dilute $HN{O_3}$ . The gas thus formed reacts with oxygen to give brown fumes $(Y)$ . $(Y)$ When dissolved in water gives an important acid \[(Z)\] and the gas $(X)$ . $X,Y\& Z$ respectively are:
A.$NO;N{O_2},HN{O_3}$
B.$N{O_2};NO,HN{O_3}$
C.${N_2}O;NO,HN{O_2}$
D.$NO;{N_2}O,HN{O_3}$

Answer 1

Hint: We need to know that the copper is a reddish brown metal and is extracted from mostly copper pyrites. Its atomic number is $29$ and copper is the best conductor of heat and electricity next to silver. It is not very reactive because it is weakly electropositive (elements give electrons (not all times). Copper is a recyclable metal like aluminium.

Complete answer:
We have to remember that copper has important chemical reactions and most of the chemical reagents resists the action of copper.
Let us see the given reactions and then find out the answer,
First, copper reacts with dilute $HN{O_3}$ to give a gas. We can write the chemical equation for this chemical reaction as,
$3C{u_{(s)}} + 8HN{O_{3(aq)}} \to 3Cu{(N{O_3})_{2(aq)}} + 2N{O_{(g)}} + 4{H_2}{O_{(l)}}$
When the copper reacts with nitric acid to form copper $(II)$ nitrate, water and liberates gas, nitric oxide. From this reaction, the gas $(X)$ is nitric oxide $(NO)$ .
The gas (from the above chemical reaction) thus formed reacts with oxygen to give brown fumes $(Y)$ .
$2N{O_{(g)}} + {O_2} \leftrightarrow 2N{O_{2\left( g \right)}}$
The brown fumes come from nitric oxide $(X)$ reaction with oxygen is nitrogen dioxide, this is $(Y)$ . This is a reversible chemical reaction.
Nitrogen dioxide, $(Y)$ , When dissolved in water gives an important acid, $HN{O_3}$ , \[(Z)\] and the gas $(NO)$ , $(X)$ . The chemical reaction is,
\[3N{O_{2}} + {H_{2}}O \to 2HN{O_3} + NO\]
From the above data $X,Y\& Z$ respectively are $NO$ , $N{O_2}$ & $HN{O_3}$ .
Therefore, the option A is the correct answer.

Note:
We must remember that copper is mostly used in industries and also has other applications. Mostly in conductors in electrical wires. Copper $(II)$ nitrate is used as a catalyst in organic chemistry and also in the textiles industry. Copper is an important constituent in many metalloproteins and enzymes and plays an important role in the human body.