Which gas is usually liberated when an acid reacts with a metal?
Question.
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 ?

solution:
Hydrogen gas is usually liberated when an acid reacts with a metal.

Example,

Step 1- Take few pieces of zinc granules and add $5 \mathrm{ml}$ of dilute $\mathrm{H}_{2} \mathrm{SO}_{4}$.

Step 2 – Shake it and pass the gas produced into a soap solution. The bubbles are formed in the soap solution. These soap bubbles contain hydrogen gas.

Test for hydrogen gas. The evolved hydrogen gas can be tested by bringing a burning candle near the soap bubbles. Hydrogen gas burns with a pop sound. (Refer Active Chemistry 2.3).
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