Question

`A` mixture of `C_(3)H_(8)(g) & O_(2)` having total volume `100ml` in an Eudiometry tube is sparked `&` it is observed that a contraction of `45ml` us observed what can be the composition of reacting mixture.
A. `15" " ml" " C_(3)H_(8)" " &" " 85" " ml" " O_(2)`
B. `25" " ml" " C_(3)H_(8)" " & " "75 " "ml" " O_(2)`
C. `45 " "ml" " C_(3)H_(8)" " &" " 55" " ml" " O_(2)`
D. `55 " "ml" " C_(3) H_(8)" " &" " 45 " "ml" " O_(2)`

Answer 1

Correct Answer - A::B
`C_(3)H_(8)+O_(2)rarr100mL`
Case-I :-
Let assume `C_(3)H_(8)` is `L.R`.
`C_(3)H_(8)+5O_(2)rarr3CO_(2)+4H_(2)OH(l)`
`{:("initial",V_(1)," "V_(2),,),("fianl",0," "V_(2)-5V_(1)," "3V_(1),):}`
Vol. contraction `=V_(i)-V_(f)`
`=(V_(1)+V_(2))-(V_(2)-5V_(1)+3V_(1))`
`45=3V_(1)`
`V_(1)=15mL(C_(3)H_(8))`
`V_(2)=85mL(O_(2))`
Case-II :-
Let assume `O_(2)` is `L.R`.
`C_(3)H_(8)+5O_(2)rarr3CO_(2)+4H_(2)O(l)`
`{:("initial", " "V_(1)," "V_(2),,),("final"," "V_(1)-(V_(2))/(5)," "0," "(3)/(5)V_(2),):}`
Vol contraction `=V_(i)+V_(f)`
`=(V_(1)+V_(2))-(V_(1)-(V_(2))/(5)+(3)/(5)V_(2))`
`45=(3)/(5)V_(2)`
`V_(2)=75mL`
`V_(1)=25mL`