Question

(a) Write the balanced chemical equations for the following reactions :
(i) Action of hydrochloric acid on alumina.
(ii) Action of sodium hydroxide on alumina.
(ii) Action of steam on iron.​

Answer 1

i) The reaction is,

2Al(s)+6HCl(aq)→2AlCl3 (aq)+3H2 (g)

ii) 2NaOH+2Al+2H2O⇨2NaAlO2 +2H2

iii) 3Fe+4H2O⟶Fe3O4 + 4H2(g)

Answer 2

2Al + 6HCl → 2Al­Cl₃ + 3H₂↑

• Aluminum reacts with diluted hydrochloric acid at room temperature. The metal aluminium dissolves in hydrochloric acid, producing aluminum chloride and colorless hydrogen gas. The reaction taking place between aluminium and hydrochloric acid is irreversible. And the final products will not react with each other.

2NaOH+2Al+2H2O⇨2NaAlO2 +2H2

• Sodium aluminate and hydrogen gas are formed when sodium hydroxide reacts with aluminium metal.

3Fe+4H2O⟶Fe3O4+4H2(g)

• Generally metal react with steam to form metal oxide and hydrogen gas. Iron reacts to form iron(II,III) oxide [FeO+Fe2O3 ] and H2 gas.