NCERT Activity 3.11 Class 10 Science Explanation

In this activity, we are going to understand the reaction between metals and acid, and also compare the reactivity of metals with acids.

What Happens When Metals React with Acids?

Aim

 

To study the reaction of different metals with dilute hydrochloric acid

Materials Required

    1. Samples of metals (Mg, Al, Zn, Fe, and Cu)

    2. Dilute HCl

    3. Test tubes

    4. Sandpaper

    5. Thermometer

    6. Dropper

 

⚠️Caution

Do not take sodium and potassium as they react vigorously even with cold water. 

Procedure

We take samples of metals as we have taken in activity 3.10, except Na and K. First, we rub the surface of the metals with sandpaper to clean them. Now we place each sample in a separate test tube and add dilute hydrochloric acid. We observe the changes.

 Observation 

 Explanation

Metals react with acid to produce salt and hydrogen gas. The reaction is exothermic.

 

Metals + Acid→ Salt + Hydrogen gas

Mg + 2HCl →MgCl₂ +H₂

2Al + 6HCl→ 2AlCl₃ + 3H₂

Zn + 2HCl→ZnCl₂ + H₂

(i) Mg reacts most vigorously, followed by Al, Zn, and then Fe.

(ii)  Copper did not react at all, so no bubbles were seen, and the temperature remained unchanged.

(iii)  Temperature increased in cases of all the metals that react with dilute acid, showing that the reactions are exothermic.

(iv)The temperature rise is maximum in the case of magnesium.

(v)   The order of reactivity with dilute HCl is

         Mg > Al > Zn > Fe > Cu

 

Conclusion

This activity explains that metals produce salt and hydrogen gas when they react with dilute acid, like hydrochloric acid.  

 Frequently Asked Questions

  1. Why are sodium and potassium not taken in this activity?

Answer – Because they react violently and can cause harm.

   2. Why does copper not react with HCl?

Answer – Copper is less reactive and is below hydrogen in the reactivity series. It cannot displace hydrogen from acids.

   3. What gas is released when metal reacts with an acid?

Answer- Hydrogen gas is released when a metal reacts with an acid.

Related Topics - 

1.  Activity 3.12

2. Activity 3.10

3. Solution of Chapter 3: Metals and Non-metals

4. MCQ Questions of Chapter 3

5. Extra Questions of Chapter 3

6. Solutions of Class 10 Science all chapters