Question

When zinc metal is treated with a dilute solution of a strong acid, a gas is evolved, which is utilized in the hydrogenation of oil. Name the gas evolved. Write the chemical equation of the reaction involved and also write a test to detect the gas formed.

Answer 1

Reaction of metal with acid:

• When a metal reacts with a strong acid, it produces its metallic salt and hydrogen gas is evolved.
• Hydrogen gas is utilized in the hydrogenation of oil.
• The general chemical reaction can be depicted as:

$\mathrm{Metal}+\mathrm{Acid}\to \mathrm{Salt}+\mathrm{Hydrogen}$

The reaction of Zinc with strong acid:

• When Zinc reacts with hydrochloric acid $\left(\mathrm{HCl}\right)$, Zinc chloride$\left({\mathrm{ZnCl}}_2\right)$ is formed along with the liberation of hydrogen$\left({\mathrm{H}}_2\right)$ gas.
• The chemical reaction can be depicted as:

$\mathrm{Zn}\left(\mathrm{s}\right)+2\mathrm{HCl}\left(\mathrm{aq}\right)\to {\mathrm{ZnCl}}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$

• Hydrogen is a colorless gas that burns with a pop sound.

Test for the detection of Hydrogen gas:

• The test for hydrogen gas can be done by bringing the candle near the source of hydrogen.
• So, hydrogen gas burns with a poppy sound.