Chemistry Q62 – JEE-MAIN 2025

Home Chemistry Basic ChemistryQuestion #77

On combustion

0.210 g

of an organic compound containing C, H and O gave

0.127 g H_{2} O

and

0.307 g C O_{2}

. The percentages of hydrogen and oxygen in the given organic compound respectively are:

Clue 1 of 3: Combustion Analysis Principle

In combustion analysis, all carbon in the organic compound is converted to $C O_{2}$ and all hydrogen to $H_{2} O$ . Oxygen is determined by difference.

🧠 Full Solution Path

Step 1: Calculate masses of C and H✦ Active

First, determine the mass of carbon and hydrogen present in the organic compound from the masses of $C O_{2}$ and $H_{2} O$ produced, respectively. Use the standard atomic masses ( $C = 12, H = 1, O = 16$ ). Molar mass of $C O_{2} = 44 g/mol$ , Molar mass of $H_{2} O = 18 g/mol$ .

Mass of C = 0.307 g C O_{2} \times \frac{12 g C}{44 g C O_{2}} = 0.083727 g

Mass of H = 0.127 g H_{2} O \times \frac{2 g H}{18 g H_{2} O} = 0.014111 g

Step 2: Calculate mass and percentage of O○ Expand

Next, calculate the mass of oxygen in the organic compound by subtracting the masses of carbon and hydrogen from the total mass of the compound. Then, determine the percentage of oxygen.

Mass of O = Mass of compound - Mass of C - Mass of H

Mass of O = 0.210 g - 0.083727 g - 0.014111 g = 0.112162 g

% O = \frac{0.112162 g}{0.210 g} \times 100 = 53.41 %

Step 3: Calculate percentage of H and identify the option○ Expand

Finally, calculate the percentage of hydrogen in the organic compound and compare with the given options.

% H = \frac{0.014111 g}{0.210 g} \times 100 = 6.72 %

The percentages of hydrogen and oxygen are approximately 6.72 % and 53.41 % respectively, which corresponds to option 4.

✦ STEM Console utilizes AI models to generate step-by-step explanations and math clues. AI can make mistakes.

Chemistry Question 62 – JEE-MAIN 2025

Clue 1 of 3: Combustion Analysis Principle

🧠 Full Solution Path