Question

It is found that in 11.2 L at 0°C and 1 atm, of any gaseous compound of 'X', there is never less than 15.5 gm of 'X'. It is also found that 11.2 L of vapours of 'X' at 0°C and 1 atm, weighs 62 gm. The atomicity of 'X' is ______.

Options

• 4

• 2

• 3

• 0

Answer 1

It is found that in 11.2 L at 0°C and 1 atm, of any gaseous compound of 'X', there is never less than 15.5 gm of 'X'. It is also found that 11.2 L of vapours of 'X' at 0°C and 1 atm, weighs 62 gm. The atomicity of 'X' is 4.

Explanation:

11.2 L at 0°C and 1 atm of compound ⇒ `1/2` mole 'X' is always ≥ 15.5 g

∴ In 1 mole of compound of 'X' ≥ 31 g

∴  Atomic weight of 'X' = 31

(in one mole of compound of any element there should always be 1 mole of atoms of that element)

Also, 11.2 L of vapour of 'X' weighs ⇒ 62g

(At 0°C, 1 atm) `(1/2 "mole")`

∴ Molecular weight of 'X' = 124

Atomicity of 'X' = `124/31` = 4