1. Reaction of a metal with dilute acid:
* Materials:
* Dilute hydrochloric acid (HCl) or dilute sulfuric acid (H₂SO₄)
* Zinc granules (Zn) or magnesium ribbon (Mg)
* A conical flask or a test tube
* Delivery tube
* A gas jar or beaker filled with water (to collect the hydrogen gas)
* Procedure:
1. Place the metal (Zn or Mg) in the flask.
2. Add the dilute acid.
3. The reaction will produce hydrogen gas.
4. Collect the hydrogen gas by displacement of water.
* Chemical Equation:
* Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)
* Mg(s) + H₂SO₄(aq) → MgSO₄(aq) + H₂(g)
2. Reaction of sodium with water:
* Materials:
* Sodium metal (Na)
* Water (H₂O)
* A petri dish
* A gas jar or beaker filled with water (to collect the hydrogen gas)
* Procedure:
1. Carefully place a small piece of sodium metal in the petri dish.
2. Add a few drops of water.
3. The reaction will be vigorous, producing hydrogen gas and heat.
4. Collect the hydrogen gas by displacement of water.
* Chemical Equation:
* 2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)
3. Electrolysis of water:
* Materials:
* Water (H₂O)
* Two electrodes (e.g., graphite rods)
* A battery or power supply
* A beaker
* Two test tubes filled with water (to collect the gases)
* Procedure:
1. Fill the beaker with water.
2. Connect the electrodes to the battery or power supply.
3. Submerge the electrodes in the water.
4. Turn on the power supply.
5. Hydrogen gas will be produced at the negative electrode (cathode) and oxygen gas at the positive electrode (anode).
6. Collect the gases in the test tubes.
* Chemical Equation:
* 2H₂O(l) → 2H₂(g) + O₂(g)
Safety Precautions:
* Always wear safety goggles to protect your eyes.
* Work in a well-ventilated area.
* Handle acids and sodium metal with care.
* Do not collect hydrogen gas in a closed container, as it can be explosive.
Note: The choice of method depends on the available materials and the desired purity of the hydrogen gas. The reaction of metals with acids is the most common method for laboratory preparation.
