Question

An organic compound on combustion gives 0.22 g of CO₂ and 0.126 g of H₂O. If the percentage of C in given organic compound is 40%, the percentage of H will be?

Answer 1

Given:
CO₂ = 0.22 g
H₂O = 0.126 g
% of C = 40%

Step 1: Mass of carbon from CO₂
Molar mass CO₂ = 44, C = 12
\[ \text{Mass of C} = \frac{12}{44} \times 0.22 = 0.06 \text{ g} \]

Step 2: Find mass of compound
\[ \frac{0.06}{\text{mass of compound}} = 40\% \] \[ \text{Mass of compound} = \frac{0.06}{0.4} = 0.15 \text{ g} \]

Step 3: Mass of hydrogen from H₂O
Molar mass H₂O = 18, H = 2
\[ \text{Mass of H} = \frac{2}{18} \times 0.126 = 0.014 \text{ g} \]

Step 4: Percentage of hydrogen
\[ \%H = \frac{0.014}{0.15} \times 100 \approx 9.33\% \]

Final Answer: 9.33%