10\, mL of gaseous hydrocarbon on combustion gives 40\, mL of CO 2(g) and 50\, mL of water vapour. Total number of carbon and hydrogen atoms in the hydrocarbon is:

Chemistry · Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry

JEE Main 2024 — 1 February, Shift 2 — Question 83

$10\,\mathrm{mL}$ of gaseous hydrocarbon on combustion gives $40\,\mathrm{mL}$ of $\mathrm{CO_2(g)}$ and $50\,\mathrm{mL}$ of water vapour. Total number of carbon and hydrogen atoms in the hydrocarbon is:

Answer: 14

Numerical answer — enter this value.

Step-by-step solution

Let the hydrocarbon be $\mathrm{C_x H_y}$ .

On combustion:

\mathrm{C_x H_y + \left(x + \frac{y}{4}\right)O_2 \rightarrow xCO_2 + \frac{y}{2}H_2O}

By Avogadro’s law, volume ratios are equal to mole ratios.

\frac{40}{10} = x \Rightarrow x = 4

\frac{50}{10} = \frac{y}{2} \Rightarrow y = 10

Total number of carbon and hydrogen atoms $= x + y = 4 + 10 = 14$

Thus, the correct answer is $14$ .

Answer key and solution verified before publishing.

Practise Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Solve a similar one free

Exam: JEE Main 2024
Paper: 1 February, Shift 2
Subject: Chemistry
Chapter: Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry
Topic: Chemical Equations, Stoichiometry and Limiting Reagent