Activity 2.4 Class 10 Science

This activity demonstrates the reaction between zinc and sodium hydroxide has been taken from the chapter Acids, Bases and Salts.

Reaction between Zinc and Sodium Hydroxide

Aim of the activity

To observe the reaction between metals and bases and test the gas evolved in the activity.

Materials used in the activity

   1. Zinc

   2. Sodium hydroxide solution

   3. Test tubes

   4. Test tube holder

   5. Bunsen burner or spirit lamp

   6. Beaker

   7. Soap solution

   8. Dropper

   9. Matchstick or candle

Procedure

We take a few pieces of granules of zinc metal in a test tube and arrange them in a test tube holder. Now add 2 mL of sodium hydroxide solution to the test tube and observe the surface of the zinc granules.

 A delivery tube from the test tube is inverted in the soap solution.

Observation

We can see bubbles on the surface of zinc granules. A gas is evolved in the reaction between zinc and sodium hydroxide solution.

Test for the evolving gas

The gas is passed into the soap solution, and the gas bubbles are formed. When a burning candle or matchstick is brought near the bubbles, they burst into a ‘pop’ sound.

Explanation

Zinc reacts with sodium hydroxide to form sodium zincate and hydrogen gas.

2NaOH(aq)       +    Zn(s)           →   Na2ZnO2(aq)    +    H2(g)

Sodium hydroxide   Zinc                   Sodium zincate

The hydrogen gas gets trapped in the soap film so the bubbles are formed.

When a burning candle or matchstick is brought near these bubbles, they burst with a ‘pop’ sound. This confirms the presence of hydrogen gas because hydrogen gas is a highly inflammable gas.

Conclusion

This activity demonstrates the reaction between metal ‘zinc’ and a base ‘sodium hydroxide solution’.

Frequently Asked Questions

   1. What does the ‘pop’ sound indicate?

Answer – The ‘pop’ sound indicates the presence of hydrogen gas.

   2. Can this activity be done with other metals?

Answer – Yes, it is possible, but zinc is amphoteric in nature, and it reacts with both acids and bases.

   3. Which salt is formed in this activity?

Answer -  Sodium zincate (Na2ZnO2)

   4. Name the gas that evolved when metal reacts with a base.

   Answer-  Hydrogen gas

   5. Give the chemical equation for the reaction.

   Answer – Zn + NaOH → Na2ZnO2 + H2

   

   6. Name the reaction in activity 2.4, class 10 science.

   Answer -  Displacement reaction

   

Related Topics 

1.  Activity 2.5

2. Activity 2.3

2. Solutions of Chapter 2 

3. MCQ Questions of Chapter 2

4. Extra Questions of Chapter 2