# Answer to Question #21205 in Physical Chemistry for EKANSH

Question #21205

Q. A gas mixture of 3 litres of propane and butane on complete combustion at 25'C produces 10 litres of CO2. Initial composition of propane and butane in the gas mixture is-
(i) 66.66%,33.33% (ii) 33.33%,66.66% (iii) 50%,50% (iv) 60%,40%

Expert's answer

The reactions propane and butane with oxygen:

C

C

If volume of propane is x , the volume of butane is 3-x. Than

volume of CO

x 3x

C

(3-x) 5*(3-x)

C

Total volume of CO

3x + 4*(3-x) = 10

3x + 12 - 4x = 10

-2x = -2

x = 2

Initial composition of propane is 2.0/3*100 = 66.66%

Initial composition of butane is 33.34%

C

_{3}H_{8}+ 5O_{2}--> 3CO_{2}+ 4H_{2}OC

_{4}H_{10}+ 6.5O2 --> 5H_{2}O + 4CO_{2}If volume of propane is x , the volume of butane is 3-x. Than

volume of CO

_{2}isx 3x

C

_{3}H_{8}+ 5O_{2}--> 3CO_{2}+ 4H_{2}O(3-x) 5*(3-x)

C

_{4}H_{10}+ 6.5O_{2}--> 5H_{2}O + 4CO_{2}Total volume of CO

_{2}is:3x + 4*(3-x) = 10

3x + 12 - 4x = 10

-2x = -2

x = 2

Initial composition of propane is 2.0/3*100 = 66.66%

Initial composition of butane is 33.34%

## Comments

Assignment Expert22.08.18, 12:01Thank you Crischal

Crischal22.08.18, 04:06For total volume of co2

3x+4(3-x)=10 should be written not 3x+5(3-x)=10.So please correct the solution.

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