Question

Equivalent weight of a divalent metal is 24 the volume of hydrogen liberated at stp by 12g of the same metal when added to excess of an acid solution is

Answer 1

Answer:- Volume of hydrogen gas produced at STP is 5.6 L.

Solution:- Equivalent weight of the divalent metal is 24. Divalent means the valence is 2.

molecular weight = equivalent weight * valence

molecular weight of metal = 24*2 = 48 grams per mol

mass of the metal = 12 g

moles of metal = $12g(\frac{1mol}{48g})$

moles of metal = 0.25 mol

Let the metal is represented by M and the hydrogen acid as HA, the reaction to produce hydrogen gas is:

$M+2HA\rightarrow MA_2+H_2$

From this equation, there is 1:1 mol ratio between metal and hydrogen gas.

So, moles of hydrogen gas produced are aslo 0.25.

At STP, volume of 1 mol of a gas is 22.4 L. Now we can calculate the volume for 0.25 moles of the gas as:

$0.25mol(\frac{22.4L}{1mol})$

= 5.6 L

Answer 2

Equivalent weight =

valency

molecular weight

​

24=

2

M

w

​

​

M

w

​

=48= Molecular weight of divalent metal X

Moles of X=

48

12

​

=0.25

X+2HCl→XCl

2

​

+H

2

​

0.25 0.50 − −

0.25 0.25

Moles of H

2

​

produced =0.25 moles

Volume of 0.25 moles H

2

​

=0.25×22.4=5.6 litres