Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store
seo-qna
SearchIcon
banner

At 300K and 1 atmospheric pressure, 10 mL of a hydrocarbon requires 55 mLof O2 for complete combustion and 40 mL of CO2 is formed. Then, the formula of the hydrocarbon is:
A. C4H8
B. C4H7Cl
C. C4H10
D. C4H6

Answer
VerifiedVerified
510k+ views
2 likes
like imagedislike image
Hint: We all know that hydrocarbon is an organic compound which consists of carbon and hydrogen atoms in particular. Both of these atoms are bonded with covalent bonds. So, while solving the above question we need to consider different types of chemical reactions and try to balance the x and y components of a hydrocarbon.

Complete step by step answer:
As we all have studied there are different types of chemical reactions. So, let’s consider the general reaction to be
A+BC+D
Now, according to the question let’s place the values of A, B, C, and D in the reaction.
Hydrocarbon + OxygenCarbon dioxide + Water
Now, let’s write their chemical formulas
CxHy+O2CO2+H2O
So, to balance the x of a hydrocarbon we have to balance the whole chemical equation.
The equation used:
CxHy(g)+(x+y/4)O2xCO2+4/2H2O
In the question, they given that the hydrocarbon =10 mL, Oxygen =55 mL, Carbon dioxide = 40 mL
According to the question let’s consider the reactants side to calculate the products mol value.
Firstly, we will take Hydrocarbon:
1 mL of the hydrocarbon = x mL of CO2 produced which implies that
1 mL of the hydrocarbon = 10(x) mL of CO2produced
Thus, 10 x = 40 mL
So, X= 4 mL
Therefore, we found the value of x.
Now, let’s consider for Oxygen:
(x+y/4)O2 ml of oxygen is required = produces x mL of CO2
55ml=x(x+y/4)×55 mL ofCO2
We can simplify this step by cross multiplication.
x(x+y/4)×55=40
55x = 40x + 10y
55x  40x = 10y
15x = 10 y
Here, we can substitute the value of x.
Asx = 4 mL, so the equation becomes
15×4 = 10y
60 = 10y
y= 6 mL
But according to the question we had to determine the chemical formula of a hydrocarbon. So, we will substitute the respective values of x and y in the formula to complete it.
Formula of hydrocarbon = CxHy
Hence, the formula of hydrocarbon becomes C4H6
Option D is the correct answer.

Note:
We must know that combustion analysis is a common analysis method for hydrocarbon. We can use this to analyze samples of unknown chemical formulas. It requires only milligrams of a sample. So we have to weigh the sample and then fully combust at a high temperature in the presence of excess oxygen, which produces carbon dioxide and water.