Question

A solid element burns completely in oxygen to give
gaseous oxide without any change in volume. If the
vapour density of oxide is 32. the equivalent weight
of element would be
(1) 8
(2) 24
(3) 32
(4) 16​

Answer 1

Answer : The correct option is, (4) 16

Explanation : Given,

Vapor density of oxide = 32

First we have to calculate the molar mass of metal oxide.

$\text{Molar mass of metal oxide}=2\times \text{Vapor density of metal oxide}$

$\text{Molar mass of metal oxide}=2\times 32=64$

As we know that, in oxide there are 2 atoms of oxygen.

So, the mass of oxide = 2 × molar mass of oxygen = 2 × 16 = 32

The mass of metal = Mass of metal oxide - Mass of oxide = 64 - 32 = 32

The mass of metal is 32 that means the metal will be sulfur and the metal oxide will be, $SO_2$.

Now we have to calculate the equivalent weight  of element.

$\text{Equivalent weight  of element}=\frac{\text{Molar mass of element}}{n}$

where,

n = valency factor = 2  (For sulfur)

$\text{Equivalent weight  of element}=\frac{32}{2}=16$

Therefore, the equivalent weight  of element would be, 16

Answer 2

Answer: 8

Explanation: We can find it out by the principle of equivalence

i.e weight/equivalent weight = constant.