Activity Project: Study of Reaction Between Hydrochloric Acid and Zinc

Objective

To investigate how the concentration of hydrochloric acid affects the rate of reaction with zinc metal.

Materials Required

• Zinc granules or strips
• Hydrochloric acid (different concentrations – 0.5M, 1M, 1.5M, 2M)
• Conical flask
• Gas measuring apparatus or delivery tube with water trough (to collect evolved hydrogen gas)
• Measuring cylinder
• Stopwatch or timer
• Thermometer

Procedure

1. Take fixed amount of zinc granules (e.g., 1 g) in a conical flask.
2. Add 20 mL of 0.5M hydrochloric acid to the flask, starting the stopwatch simultaneously.
3. Collect the evolved hydrogen gas using the gas delivery tube setup in the water trough.
4. Record the volume of hydrogen gas evolved at regular intervals (e.g., every 30 seconds) until the reaction completes.
5. Repeat steps 1-4 for hydrochloric acid concentrations of 1M, 1.5M, and 2M.
6. Plot a graph of volume of hydrogen gas evolved vs time for each concentration.

Observations

Concentration of HCl (M)	Time (minutes)	Volume of H₂ gas evolved (mL)
0.5	0.5	10
0.5	1.0	18
1.0	0.5	20
1.0	1.0	35
1.5	0.5	27
1.5	1.0	45
2.0	0.5	34
2.0	1.0	58

Result

The rate of reaction between zinc and hydrochloric acid increases as the concentration of hydrochloric acid increases, which is evident from the increased volume of hydrogen gas evolved over the same time intervals.

Precautions

• Use freshly prepared hydrochloric acid solutions.
• Keep the amount of zinc constant across all trials for fair comparison.
• Measure gas volume accurately using water displacement.
• Conduct the experiment away from direct sunlight and drafts to avoid interference.
• Wear safety goggles and gloves during the experiment.