Materials required: test tube, delivery tube, glass trough, candle,soap water, dil HCI, and zinc granules, cork.
Procedure: Set the apparatus as shown in fig. 1.
-Take about 10ml of dilute HCl in a test tube and add a few zine granules to it.
- What do you observe on the surface of the zine granules?
- Pass the gas being evolved through the soap water.
- Why are bubbles formed in the soap solution?
- Bring a burning candle near the gas filled bubble.
What do you observe?
You will notice the gas evolved burns with a pop sound indicating H 2The chemical reaction of the above activity is
Acid + Metal →Salt + Hydrogen
2 HCl(aq)+ Zn(s)→ZnCl2(aq)+ H(g)
Repeat the above experiment with some other acids like H2SO4 and HNO3
From the above activities you can conclude that H2 gas is evolved whenacid reacts with metal
Place a few granules of zine metal in one of the test tubes and add 10 ml of sodium hydroxide (NaOH) solution and warm the contents of the test tube
Repeat the rest of the steps as in activity-2 and record your observations
In this activity also you will notice and salt formed is sodium zincate that evolved gas is hydrogen (H2)
The reaction is written as follows. 2 NaOH + Zn → Na2ZnO2H2 (Sodium zincate)
However, such reactions are not possible with all metals.