Question

20 mL of a mixture of CO and H2 were mixed with excess of O2 and exploded and cooled. There was a volume contraction of 18 mL. All volume measurements corresponds to room temperature (27 C) and one atmospheric pressure. Determine the volume ratio V1 : V2 of CO and H2 in the Original Mixture.
(A) 1 : 2
(B) 3 : 2
(C) 2 : 3
(D) 4 : 1
NOTE- ANSWER IS NOT 9:1 OR 1:9. QUESTION IS CORRECT.

Answer 1

Answer:

Ratio is 3:2.

Explanation:

Since, the reaction is 2CO + O2 is 2CO2 and again another reaction is 2H2 + O2 is 2H2O.

Now we let that the volume of CO is x so volume of H2 is (20-x) when excess O2 is given in this reaction then the entire reaction is completed thus we get the initial volume to be 3x/2 mL.

Now, for the second reaction the initial volume will be 30 - 3x/2 and hence the total volume of reaction will be 3x/2 +30 - 3x/2 = 30. And the volume of the product is x mL.

So we know that the volume of contraction is volume of reaction - volume of product.

18 = 30 -x.

So, x = 12.

Hence, volume of CO is 12 and the volume of H2 is 20 - 12 = 8.

So, ratio of volume of Co to H2 is 12/8 = 3:2.