Question

When a zinc strip is kept immersed in a test tube in freshly prepared copper sulphate solution taken in a test tube. After 1 hour the colour of solution was observed to change​

Answer 1

Explanation:

When a strip of zinc metal is immersed in copper sulphate solution, then the blue colour of copper sulphate solution fades gradually because of the formation of zinc sulphate solution (colourless), and red-brown copper metal is deposited on the zinc strip.

Chemical equation :-

CuSO4 (aq.) + Zn (s) → ZnSO4 (aq.) + Cu (s)

Therefore,

After 1 hour the colour of solution changed from blue to colourless.

This is the example of Displacement reaction.

Additional information :-

Types of chemical reaction :-Combination reaction -

• Those reaction in which two or more substances combined to form a single substance, are called combination reaction.

Example -

C + O2 → CO2

Decomposition reaction -

• Those reaction in which a compound splits up into two or more simpler substances are known as decomposition reaction.

Example -

CaCO3 → CaO + CO2

Displacement reaction -

• Those reaction in which one element takes the place of another element in a compound, are known as Displacement reaction.

Example -

CuSO4 + Zn → ZnSO4 + Cu

Double Displacement reaction -

• Those reaction in which two compounds react by an exchange of ions to form two new compounds are called double displacement reaction.

Example -

AgNO3 + NaCl → AgCl + NaNO3