Question

When copper turnings are added to the silver nitrate solution, a blue-coloured solution is formed after some time. It is because copper:
(A)- displaces silver from the solution
(B)- forms a blue colored complex with $AgN{O_3}$
(C)- is oxidized to$C{u^{2 + }}$
(D)- is reduced to $C{u^{2 + }}$

Answer 1

Hint: Silver nitrate is an inorganic compound. This salt is a versatile precursor to many other silver compounds, such as those which are used in photography. It is also far less sensitive to light than halides.

Complete step by step solution:
From a vast number of reactions done by silver nitrate, one of those reactions is with copper. Here, we suspend a rod of copper in a solution of silver nitrate and leave it for a few hours. The silver nitrate reacts with copper to form crystals of silver metal and a solution of copper nitrate:
$2AgN{O_3} + Cu \to Cu{(N{O_3})_2} + 2Ag$
Let’s have a basic knowledge about the product called Copper nitrate.
Copper nitrate is an inorganic compound that forms a blue crystalline solid. Anhydrous copper nitrate forms deep blue-green crystals and sublimes in a vacuum. Copper nitrate also occurs as five different hydrates, the most common of them is the hemi-pentahydrate and trihydrate. These materials are more commonly encountered in commerce than in the laboratory.
Now, according to the above reaction, the nitrate of silver is converted into nitrate of copper i.e. silver is displaced by copper. Therefore, it is a displacement reaction.
Also, the oxidation state of copper before the reaction was 0 and it gets oxidized after the reaction and attains an oxidation state of +2. Also, the oxidation state of silver before the reaction was +2 but during the reaction, it gets reduced so its oxidation state becomes 0. So, there was oxidation as well as the reduction in the above chemical reaction. Therefore, this reaction is a type of redox reaction.

So, from the above discussion, we can say that the answer to the given question is both (A) and (C).

Note: In this case, copper acted as a reducing agent. Always be clear about the term reducing agent. Most of the students get confused and think that reducing agents get reduced but the reality is just opposite i.e. reducing agents gets oxidized and reduces the other compound.