Question

What will happen when Zinc and Hydrochloric acid reacts?
Can anyone explain with full procedure of experiment?​

Answer 1

When Zinc reacts with Hydrochloric acid formation of zinc chloride and Hydrogen gas takes place.

The above reaction is an example of Displacement Reaction.

Take a test tube and add zinc granules in it. Add Hydrochloric acid in it and then lose the mouth of the test tube using a cork.

Bubbles of Hydrogen gas will form.

How to check the presence of Hydrogen gas?

When a burning candle is brought near the test tube, it burns with a 'POP' sound. This confirms the presence of hydrogen gas.

The following reaction will takes place:

Zn + 2HCl → ZnCl2 + H2

Difference between Displacement Reaction and Double Displacement Reaction:

Fe + CuSO4 → FeSO4 + Cu

Here, iron displaces copper from copper sulphate in it's aqueous solution and gives ferrous sulphate and copper metal. The above reaction is an example of Displacement Reaction.

• General equation for displacement reaction is A + BC → B + AC (one displacement takes place).
• It is a slow reaction.
• Change in colour takes place and no precipitation is formed in it.

Pb(NO3)2 + 2KI → PbI2 + 2KNO3

The given reaction is an Double Displacement Reaction. As the ions are displacing each other. Also it is a Precipitation Reaction as yellow precipitates of Lead (II) Iodine are formed.

• General equation for double displacement reaction is AB + CD → AD + CB (two displacement takes place).
• It is a fast reaction.
• Formation of precipitation takes place