Question

At 27°C vapour density of the mixture of NO₂ and N₂O₄ is 38.3. Calculate the moles of NO₂ in 100 g mixture. 

Answer 1

Vapour density of mixture = 38.3

Molecular mass of mixture = 2 38.3

Mass of mixture = 100 g

Number of moles present = 100/2 x 38.3...(1)

Suppose mass of NO a gram

Mass of N₂O₄ (100 – a)gram

Moles of NO₂ = w / M  = a / 46

Moles of N₂O₄ = w / M (100 - a)/92