Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?
Answer: When acid reacts with metal, it liberates hydrogen gas usually. This can be shown by following activity:
- Take some zinc granules in the test tube and pour sulphuric acid in it.
- Allow the gas pass through the solution of soap.
- When gas starts coming out from the soap solution bubbles are formed.
- Bring a burning candle near the bubbles of gas it burns with a pop sound.
- Burning of gas with pop sound proves that it is hydrogen gas.
Reaction involved in this process can be written as follows:
Zn + H2SO4 ⇨ ZnSO4 + H2