Question

6) 1 mole of metal 'M' reacts completely with alcohol to give 1.5 moles of H2. Then
what will be the valency of metal 'M'?
(A) 4
(B) 3
(C) 2
(D) 1​

Answer 1

Answer:

I'll

4

Explanation:

1 mole of metal reacts metals

Answer 2

(B) The valency of the metal is 3.

Explanation:

• On the reaction of metal and the alcohol, the metal replaces the hydrogen ion of the alcohol, and liberates hydrogen gas.
• The reaction can be written as: $M^{n+}+R-OH\rightarrow (R-O)_{n}M+\frac{1}{2} H_{2}$
• If one mole of metal gives 3/2 moles of hydrogen, it can be written as: $M\rightarrow M^{3+}+3e^{-}$
• These three electrons will take part in hydrogen gas formation as:  $3H^{+}+3e^{-}\rightarrow \frac{3}{2}H_{2}$
• Therefore, the valency of metal is 3, and option B is correct.