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KCET · Chemistry · States of Matter

A gas mixture contains \(25 \%\) He and \(75 \% \mathrm{CH}_{4}\) by volume at a given temperature and pressure. The percentage by mass of methane in the mixture is approximately____

  1. A \(75 \%\)
  2. B \(25 \%\)
  3. C \(92 \%\)
  4. D \(8 \%\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(92 \%\)

Step-by-step Solution

Detailed explanation

Gas mixture contains \(25 \%\) He and \(75 \% \mathrm{CH}_{4}\) by volumes. We have to calculate the mass percentage of methane in the mixture.
molar mass of \(\mathrm{He}=4\)
molar mass of \(\mathrm{CH}_{4}=16\)
\(\therefore\) Mass percentage of methane in the mixture shall be \(=\frac{75 \times 16}{25 \times 4+75 \times 16} \times 100=92 \%\)