Question

The weight if 2.8 litres of a gas at NTP is 3.50 g. Its vapour density is

a) 20 b) 32 c) 14 d) 28​

Answer 1

Answer:

14 is my answer

Explanation:

wt/ GMW= vol/22.4

3.5/x=2.8/22.4 x= 28 - by solving this

molecular mass = vapour density x 2

vapour density= 28/2 = 14

Answer 2

Answer:

option c

Explanation:

volume of gas is 2.8 litres  

we know 1 mole = 22.4 litres so 2.8 litres will be equal to 1/8 moles

now given weight is 3.5 gram

we know that moles = given weight/molecular weight

so  1/8 = 3.5/molecular weight

so molecular weight is 8 * 3.5= 28 u

we also know that vapour density  is given by molecular weight/2

so VD= 28/2 = 14

so final answer is option c 14

• NOTE vapour density is ratio of molecular weight of element with weight of hydrogen gas that is 2u