Question

2.
Which gas is usually liberated when an acid reacts with a metal? Illustrate with example. how will you test for the presence of this gas ?​

Answer 1

We need to tell , which gas is usually liberated , when an acid reacts which a metal . Let us take the Reaction of , Hydrochloric acid and Zinc . The Reaction would be ,

$\sf\dashrightarrow 2HCl + Zn \to ZnCl_2 + \pink{H_2}$

We know that , Zinc is more reactive than Hydrogen , so it will displace Hydrogen. Therefore Hydrogen is released in the form of gas.

Now let us see the reaction of Hydrochloric acid and Mg .

$\sf\dashrightarrow 2HCl + Mg \to MgCl_2 + \pink{H_2}$

Here , again Magnesium is more reactive than , H , therefore Mg will displaces H . Again , we see that , Hydrogen is liberated in the form of gas.

• Basically , all acids have Hydrogen atoms. And all metals which are more reactive than Hydrogen will replace it . To test the presence of Hydrogen gas , bring a burning matchstick near the test tube . We will hear , pop up sound.