Question 2 Page 6 (iii) - Chapter 1 Class 10 - Chemical Reactions and Equations

Write the balanced equation for the following chemical reactions.

(iii) Sodium + Water → Sodium hydroxide + Hydrogen

Answer

(iii) Sodium + Water → Sodium hydroxide + Hydrogen

The skeletal chemical equation of the above reaction is

Na + H ₂ O  →  NaOH + H ₂

1. Number of atoms of Hydrogen in reactants ≠ number of atoms of Hydrogen in products
   To balance number of Hydrogen,
   We multiply the NaOH in the product by 2 (If H2 is multiplied, the total number of H in the product will be odd while that in the reactant is even. This will make balancing difficult.)
   The chemical equation becomes
   
   Na + H ₂ O  →  2 NaOH + H ₂

2. Now ,
   Number of atoms of Sodium in reactants ≠ number of atoms of Sodium in products
   To balance number of Sodium,
   We multiply the Na in the Reactants by 2
   The chemical equation becomes
   
   2 Na + H ₂ O  →  2 NaOH + H ₂

3. Now,
   Number of atoms of Hydrogen in reactants ≠ number of atoms of Hydrogen in products
   To balance Hydrogen and Oxygen,
   We multiply H ₂ O in the Reactants by 2
   
   2 Na + 2 H ₂ O  →  2 NaOH + H ₂

Now, all the elements are balanced and the balanced equation is

2 Na + 2 H ₂ O  →  2 NaOH + H ₂

2 Na + 2 H ₂ O  →  2 NaOH + H ₂