Question

Calculate the volume of air, containing 21% of oxygen by volume required for the complet combustion of 10L of ethylene under similar conditions

Answer 1

Combustion of ethylene is given by the equation
`C_(2)H_(4)+3O_(2) rarr 2CO_(2) +2H_(2)O`
one volume of `C_(2)H_(4) =3` volumes of `O_(2)`
10ml of `C_(2)H_(4) = ?`
The volume of `O_(2)` required for the combustion of
10L of `C_(2)H_(4) = 10 xx 3 = 30L`
But air contains only `21% O_(2)` by volume
21L of `O_(2) = 100L` of air
30L of `O_(2) = (30)/(21) xx 100 = 142.86L`