Question

What happens when dilute sulphuric acid is poured on zinc granules?

Answer 1

Hint :Try to recall how metal reacts with acid. Generally metals reacting with acid a salt is formed and there is no formation of water unlike the reaction between acid and bases. When metal reacts with acid hydrogen gas is evolved. Regardless of the type of acid or metals reacting together hydrogen gas and a salt is formed during this reaction.

Complete Step By Step Answer:
Zinc granules are the granulated form of the metal zinc. They have high surface area and high particle size which facilitates reaction in a better way. Zinc granules are mixed with impurities of copper in a trace amount. This copper impurity also acts as a catalyst that helps to provide better reaction conditions.
This reaction of zinc with hydrogen is a main laboratory method for obtaining hydrogen.
When we pour dilute sulphuric acid on zinc granules, zinc sulphate is formed and the hydrogen gas is evolved with an effervescence.
The reaction is as follow:
$Zn(s) + {H_2}S{O_4}(aq) \to ZnS{O_4}(aq) + {H_2}(g)$
On reaction of zinc with sulphuric acid the salt formed is a white colour substance which is zinc sulphate which is also known as white vitriol. During the reaction zinc displaces the hydrogen as it is more reactive than the hydrogen. This is known as the single displacement reaction of a non-metal by a metal.
Also when zinc reacts with the sulphuric acid if you observe the test tube in which the reaction is taking place, the test tube will be hot which indicates rise in temperature during the reaction.

Note :
Hydrogen gas burns with a popping sound. To observe the presence of hydrogen gas we can burn a matchstick and bring it to the test tube on which reaction is taking place. Hydrogen being a combustible gas burns with a pop sound.