Two metals, M₁ and M₂ are found to show the following properties:

(i) M₁ liberates H₂ when it reacts with dil. sulphuric acid whereas M₂ does not do so.
(ii) Both M₁ and M₂ react with chlorine to form (M₁)Cl₂ and (M₂)Cl₂ respectively. Indicate the reaction (if any) in the following:
(i) (M₁)Cl₂ + M₂ →
(ii) (M₂)Cl₂ + M₁ →
(ii) (M₁)SO₄ + M₂ →
(iv) (M₂)SO₄ + M₁ →

i)M₁ liberates H₂ when it reacts with dil. sulphuric acid whereas M₂ does not becasue M₁ is more reactive than hydrogen thus liberates hydrogen.
whereas M₂ is less reactive than hydrogen thus it does not have tendency to liberate hydrogen.

ii)  Statement (i) shows that M₁ is more reactive than M₂ and so it will displace M₂ from its salts but not otherwise, i.e., M₂ will not displace M₁ from its salts. Therefore reaction (i) and (iii) are not possible but (ii) and (iv) will take place. M₁ and M₂ are both bivalent as seen from statement (ii). Therefore,

i)(M₁)Cl₂ + M₂ → No reaction
ii)(M₂)Cl₂ + M₁ → (M₁)Cl₂ + M₂

iii)(M₁)SO₄ + M₂ → No reaction
iv)(M₂)SO₄ + M₁ → (M₂)SO₄ + M₂.