Question

Explain the method of preparation of hydrogen gas in the laboratory.

Answer 1

Method of preparation of Hydrogen gas$\left({\mathrm{H}}_2\right)$ in the laboratory-

1. We can prepare the Hydrogen gas in the laboratory with the Dilute Hydrochloric acid$\left(\mathrm{HCl}\right)$ or Sulphuric acid$\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$ on Zinc granules$\left(\mathrm{Zn}\right)$.
2. In chemical laboratories, granulated zinc is considered the ideal compound for preparing the Hydrogen gas$\left({\mathrm{H}}_2\right)$
3. Because of the small amount of copper present in it.
4. The small amount of copper in it acts as a catalyst in the reaction and increases the rate of a chemical reaction without participating in the reaction.

Experiment procedure-

Step-1 Take a few grams of zinc granulates and place them in 500 ml of the flask

Step-2 Take a thistle funnel and add either dilute Hydrochloric acid or Sulphuric acid to the zinc granules flask.

Step-3 Attached a delivery tube to the flask and water-filled tub to form a water downward displacement system.

• Hydrogen gas started coming out when the acid is mixed with the zinc granules.
• A down displacement of water occurs when starts coming out through the delivery tube.
• It shows that Hydrogen gas is lighter than water.

The chemical reaction involves in this process are-

General format- Metal + Dilute Acid → Salt of Metal & Acid + Hydrogen

With Hydrochloric acid - $$\begin{gathered} \mathrm{Zn}\left(\mathrm{s}\right)+2\mathrm{HCl}\left(\mathrm{aq}\right)\to {\mathrm{ZnCl}}_2\left(\mathrm{s}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right) \\ \left(\mathrm{Granulated}\mathrm{Zinc}\right)\left(\mathrm{Dilute}\mathrm{Hydrochloric}\mathrm{acid}\right)\left(\mathrm{Zinc}\mathrm{chloride}\right)\left(\mathrm{Hydrogen}\mathrm{gas}\right) \end{gathered}$$

With Sulphuric acid $$\begin{gathered} \mathrm{Zn}\left(\mathrm{s}\right)+{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to {\mathrm{ZnSO}}_4\left(\mathrm{s}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right) \\ \left(\mathrm{Granulated}\mathrm{Zinc}\right)\left(\mathrm{Dilute}\mathrm{Sulphuric}\mathrm{acid}\right)\left(\mathrm{Zinc}\mathrm{Sulphate}\right)\left(\mathrm{Hydrogen}\mathrm{gas}\right) \end{gathered}$$