A 20 mL mixture of CO, `CH_4`, and Helium (He) gases is exploded by an electric discharge at room temperature with excess of oxygen. The volume contraction is found to be 13 mL. A further contraction of 14 mL occurs when the residual gas is treated wityh KOH solution. Find out the composition of the gaseous mixture in terms of volume percentage.

Options

A. `CO-40%,CH_(4)-20%, He-40%`
B. `CO-40%, CH_(4)-30%,He-20%`
C. `CO-50%,CH_(4)-20%,He-30%`
D. `CO-50%,CH_(4)-10%,He-40%`

Answer

C

Explanation

`underset("a vol")underset("1 vol")(CO(g))+underset("1/./2a vol")underset("1/2 vol")(((1)/(2))O_(2)(g))rarrunderset("a vol")underset("a vol")(CO_(2)(g))`