Question

When a strip of copper is dipped in a solution of ferrous sulphate.
A. Iron is deposited on the copper strip.
B. Copper is precipitated.
C. Copper is dissolved.
D. No reaction occurs.

Answer 1

Hint: A displacement reaction occurs when a more reactive metal undergoes a reaction with less reactive metal. In this reaction, the metal with higher reactivity causes displacement of the less reactive metals from its compound.

Complete Step by Step Answer:
Let’s first discuss the reactivity series metals. It is a list of metals and they are arranged on the basis of their reactivity. At the top, highly reactive metals such as potassium and sodium are present. And at the bottom the least reactive metals such as gold, platinum are present. The reactivity series is,
K > Na > Ca > Mg > Al > Zn > Fe > Sn > Pb > Cu

Now, we will discuss the reaction of copper with ferrous sulphate. Here, a copper strip is dipped in the ferrous sulphate solution and we have to find out the product of the reaction. From the above series, we find that the reactivity of copper is less than that of iron. Therefore, no displacement of iron from the copper sulphate happens because of copper. So, the reaction will not happen.
Hence, option D is right.

Note: It is to be noted that iron shows the variable valency. The phenomenon of variable valency defines more than one valencies exhibited by the metals such as copper and Iron. The ferrous sulphate consists of iron whose valency is 2. So, the formula of ferrous sulphate is \[{\rm{FeS}}{{\rm{O}}_{\rm{4}}}\]. And the ferric sulphate consists of iron whose valency is 3. Do, the formula of ferric sulphate is \[{\rm{F}}{{\rm{e}}_2}{{\rm{(S}}{{\rm{O}}_{\rm{4}}}{\rm{)}}_3}\].