Chapter Name: Chemical Reactions and Equations
Activity Name: Formation of hydrogen gas in Chemical Reactions and Equations
The experiment demonstrates the formation of hydrogen gas by the reaction between zinc granules and dilute hydrochloric acid.
- Zinc granules
- Dilute hydrochloric acid
- Conical flask
- Burning matchstick
Step by Step Procedure:
- Take a few zinc granules in a conical flask.
- Add about 5 ml of dilute hydrochloric acid to the conical flask.
- Observe the changes in the conical flask.
- Effervescence or bubbling will be observed in the conical flask, indicating the evolution of gas.
- Hydrogen gas (H2) is produced as a result of the chemical reaction between zinc and hydrochloric acid.
Now keep a burning matchstick near the mouth of the conical flask. • What happens to the burning matchstick? The burning matchstick extinguishes with a “pop” sound when brought near the mouth of the conical flask. This indicates the presence of hydrogen gas, which is highly flammable and supports combustion.
• Touch the bottom of the conical flask with your fingers. What do you notice? The bottom of the conical flask feels cooler. This is because the reaction between zinc and hydrochloric acid is exothermic, meaning it releases heat.
• Is there any change in temperature? Yes, there is a change in temperature. The reaction between zinc and hydrochloric acid releases heat, making the surroundings slightly warmer.
- Perform the experiment in a well-ventilated area to avoid the accumulation of hydrogen gas.
- Handle hydrochloric acid with care, as it is corrosive. Wear safety goggles and gloves while handling the acid.
- Keep a safe distance from the burning matchstick when testing for hydrogen gas.
Lesson Learnt from Experiment:
The experiment illustrates the formation of hydrogen gas (H2) by the chemical reaction between zinc and dilute hydrochloric acid. It also highlights the properties of hydrogen gas, such as its flammability, ability to support combustion, and the exothermic nature of the reaction.