JEE Main 2025 — Some Basic Concepts Of Chemistry Question with Solution

Convert the mass of ${\mathrm{CO}}_2$ to moles:

The molar mass of ${\mathrm{CO}}_2$ is 44 g/mol. Thus, the number of moles of ${\mathrm{CO}}_2$ produced is calculated as follows:

${\mathrm{n}}_{{\mathrm{CO}}_2}=\frac{220\times 10^{-3}\text{g}}{44\text{g/mol}}=5\times 10^{-3}\text{ moles}$

Calculate the mass of carbon in ${\mathrm{CO}}_2$:

Since each mole of ${\mathrm{CO}}_2$ contains one mole of carbon, the moles of carbon are the same: $5\times 10^{-3}$ moles. The molar mass of carbon is 12 g/mol, so the mass of carbon is:

${\mathrm{m}}_{\mathrm{C}}=5\times 10^{-3}\text{moles}\times 12\text{g/mol}=60\times 10^{-3}\text{g}=60\text{mg}$

Calculate the percentage composition of carbon:

To find the percentage by mass of carbon in the compound, use the formula:

$\%\text{Carbon}=\left(\frac{60\text{mg}}{500\text{mg}}\right)\times 100=12\%$

Thus, the percentage composition of carbon in the compound is approximately 12%.