Q1. 20 mL of CO was mixed with 50 mL of oxygen and the mixture was exploded. On cooling, the resulting mixture was shaken with KOH. Find the volume of the gas that is left?

40 ml

Q2. 10 mL of a gaseous hydrocarbon was burnt completely in 80 mL of O₂ at NTP. The remaining gas occupied 70 mL at NTP. This volume became 50 mL on treatment with KOH solution. What is the formula of the hydrocarbon?

C₂H₄

Q3. 7.5 mL of a gaseous hydrocarbon was exploded with 36 mL of oxygen. The volume of gases on cooling was found to be 28.5 mL, 15 mL of which was absorbed by KOH and the rest was absorbed in a solution of alkaline pyrogallol. If all volumes are measured under the same conditions, deduce the formula of the hydrocarbon?

C₂H₄.

Q4. 7.5 mL of a hydrocarbon gas was exploded with excess of oxygen. On cooling, it was found to have undergone a contraction of 15 mL. If the vapour density of the hydrocarbon is 14, determine its molecular formula?

C₂H₄

Q5. 50 mL of pure and dry oxygen was subjected to silent electric discharge  and on cooling to the original temperature, the volume of ozonised oxygen was found to be 47 mL. The gas was then brought in contact with turpentine oil, when after the absorption of ozone, the remaining gas occupied a volume of 41 mL. Find the molecular formula of ozone?

O₃

Q6. 50 mL of a mixture of CO and CH₄ was exploded with 85 mL of O₂. The volume of CO₂ produced was 50 mL. Calculate the percentage composition of the gaseous mixture if all volumes are measured under the same conditions, and the given volume of O₂ is just sufficient for the combustion of 50 mL of the mixture of CO and CH₄?

CO = 20% 

Q7. A 40 mL sample of a mixture of H₂ and O₂ was placed in a gas burette 

at 18^oC and 1 atm pressure. A spark was applied so that the formation of H₂O was complete. The remaining pure gas had a volume of 10 mL at 18^oC and 1 atm pressure. If the remaining gas was hydrogen, what was the initial mole per cent of hydrogen in the mixture?

H₂ = 75%

Q8. A sample of coal gas contained H₂, CH₄ and CO. 20 mL of this mixture 

was exploded with 80 mL of oxygen. On cooling, the volume of gases was 68 mL. There was a contraction of 10 mL when treated with KOH. Find the composition of the original mixture?

H₂ = 50%, CO = 10%, CH₄ = 40%

Q9. 1 litre of a mixture of CO and CO₂ is taken. This mixture is passed through a tube containing red hot charcoal. The volume now becomes 16 litres. The volumes are measured under the same condition. Find the composition of the mixture by volume?

CO = 0.4 litres

Q10. 10 mL of a mixture of CO, CH₄ and N₂, exploded with excess of oxygen,  gave a contraction of 65 mL. There was a further contraction of 7 mL when the residual gas was treated with KOH. What is the composition of the original mixture? 

CO = 5 ml, CH₄ = 2 ml, N₂ = 3ml

Q11. 10 ml of a mixture of CH₄ , C₂H₄ and CO₂ was exploded with excess of  air. After explosion there was a contraction of 17 mL and after treatment with KOH, there was a further reduction of 14 mL. What was the composition of the mixture? 

CH₄ = 4.5 ml, C₂H₄ = 4.0 ml, CO₂ = 1.5 ml

Q12. A mixture of formic acid and oxalic acid is heated with concentrated H₂SO₄. The gas produced is collected and on its treatment with KOH solution the volume of the gas decreased by one-sixth. Calculate the molar ratio of the two acids in the original mixture? 

HCOOH : H₂C₂O₄ : : 4 : 1

Q13. 15 mL of a gaseous hydrocarbon was required for complete combustion in 357 mL of air (21% of oxygen by volume) and the gaseous products occupied 327 mL (all volumes being measured at NTP). What is the formula of the hydrocarbon?

(C₃H₈)

Q14. 20 ml of a mixture of C₂H₂ and CO was exploded with 30 mL of oxygen. The gases after the reaction had a volume of 34 mL. On treatment with KOH, 8 mL of oxygen remained. Calculate the composition of the mixture?

(C₂H₂ : 6 mL; CO : 14 mL)

Q15. On passing 25 ml of a gaseous mixture of N₂ and NO over heated copper, 20 ml of the gas remained. Calculate the percentage of each in the mixture.

(N₂ : 60%; NO : 40%)

Q16. 40 mL of a mixture of hydrogen, CH₄ and N₂ was exploded with 10 mL of oxygen. On cooling, the gases occupied 36.5 mL. After treatment with KOH, the volume reduced by 3 mL and again on treatment with alkaline pyrogallol, the volume further decreased by 15 mL. Determine the composition of the mixture.

Q17. What volume of air is needed for the combustion of 1 metre³ of a gas having the following composition in percentage volume: 50% of H₂, 35% of CH₄, 8% of CO, 2% of C₂H₄ and 5% of noncombustible admixture? The air contains 21% (by volume) of oxygen.