Answer to Question #66365 in Inorganic Chemistry for Adrian

Question

20cm3 of a gaseous hydrocarbon X were exploded with 120cm3 of oxygen. After d explosion the volume of gases remaining was 90cm3 and this decreased to 50cm3 on treatment with aqueous potassium hydroxide. Calculate the molecular formula of X

Answer 1

Answer
1) The gases remaining after the reaction are CO₂ and O₂, otherwise the solution is not possible.
2) 90 – 50 = 40cm3 CO₂.
3) 50 cm3 O₂ left.
4) 120 – 50 = 70 cm3 O₂ reacted.
5) We compose the reaction equation:
6) 2CₓHᵧ + 7O₂ = 4CO₂ + 6 H₂O.
X=2; y=6; C₂H₆ - ethane.