Question

Explain the method of preparation of Hydrogen gas in the laboratory with chemical equation and the diagram.

Answer 1

Hint: Use dilute hydrochloric acid or dilute sulphuric acid on granulated zinc for laboratory preparation and try writing the equation.

Complete step by step answer:
Hydrogen is prepared in the laboratory by the action of the dilute hydrochloric acid or dilute sulphuric acid on granulated zinc.
Granulated zinc gives more surface area for the acid to act, so hydrogen is formed faster. Granulated zinc is ideal for the preparation of hydrogen gas in chemical laboratories because it usually contains a small amount of copper, which has the ability to act as a catalyst to the associated chemical reaction and, therefore, increase the rate of the chemical reaction without actually participating in it. A positive catalyst increases the rate of a chemical equation. This is the reason why granulated zinc is preferred over pure zinc for the laboratory preparation of hydrogen gas.

Reaction:
\[Zn~~\text{ }+~~~\text{ }2HCl~~\text{ }\to ~~\text{ }ZnC{{l}_{2}}~~\text{ }+~~\text{ }{{H}_{2}}~\uparrow \]
\[Zn~~\text{ }+~~~\text{ }{{H}_{2}}S{{O}_{4~}}~~~\to ~~~~\text{ }ZnS{{O}_{4}}~~~\text{ }+~~~\text{ }{{H}_{2}}~\uparrow \]

Hydrogen is collected by downward displacement of water as it is less dense than water. Hence it comes out at the surface of water. It is insoluble in water so it does not dissolve in water. In case of displacement with air, it is not possible even if hydrogen is lighter than air.
Diagram for the above mentioned process

Note: Hydrogen is used to process crude oil into refined fuels, such as gasoline and diesel, and also for removing contaminants, such as sulphur, from these fuels. Hydrogen is a useful energy source because it burns very cleanly, unlike fossil fuels. It does not emit dangerous gases, no carbon emissions. - Hydrogen is used in lamps, balloons, as a coolant for batteries and even in some of the most deadly weapons like hydrogen bombs.