Question

20 ml of gaseous hydrocarbon required 400 ml of air for complete combustion. The air contains 20% by volume of oxygen. The volume of gaseous mixture after explosion and cooling was found to be 380 ml. Volume of \[C{O_2}\] is:
A.40 ml
B.60 ml
C.80 ml
D.100 ml

Answer 1

Hint:There are three states of matter namely the solid, liquid and gas. All the states of matter vary drastically from each other in the type of molecular forces, the composition of the particles inside them and the way they behave on the application of the physical parameters.

Complete step by step answer:
A gaseous mixture is the one in which more than one gas is present in the reaction mixture.
The reaction of the substance with the oxygen rapidly is known as the combustion reaction.
The compounds of the carbon and hydrogen are known as the hydrocarbons.
Volume of the air=400 ml
20% of the oxygen is there in the 100 ml of the air.
Thus the volume of the Oxygen used = $ \frac{{20}}{{100}} \times 400 \\
   = 80ml \\
$
Thus out of the total volume of 380 ml of the gaseous mixture, the volume of the Oxygen in the mixture is 80 ml, thus the volume of the Carbon dioxide will be:
Let the volume of carbon dioxide be x
Total volume of the mixture= Volume of Oxygen + volume of carbon dioxide
380=80+ x
x=380-80
x=300 ml
Thus the volume of the carbon dioxide will be: $ \frac{{20}}{{100}} \times 300 \\
   = 60ml \\
$
Thus the option B will be the correct answer.


Note:
The absorption of the gases during the chemical reaction or in a reaction directly depends on the relative reactivity of the gases in comparison to each other. This in turn determines the consumption of the particular volume of the gas during the reaction.