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Question: Answered & Verified by Expert
The maximum number of molecules is present in:
ChemistrySome Basic Concepts of ChemistryNEETNEET 2004
Options:
  • A $15 \mathrm{~L}$ of $\mathrm{H}_2$ gas at STP
  • B $5 \mathrm{~L}$ of $\mathrm{N}_2$ gas at STP
  • C $0.5 \mathrm{~g}$ of $\mathrm{H}_2$ gas
  • D $10 \mathrm{~g}$ of $\mathrm{O}_2$ gas
Solution:
2919 Upvotes Verified Answer
The correct answer is: $15 \mathrm{~L}$ of $\mathrm{H}_2$ gas at STP
At STP $22.4 \mathrm{~L} \mathrm{H}_2=6.023 \times 10^{23}$ molecules
$$
\begin{aligned}
15 \mathrm{~L} \mathrm{H}_2 & =\frac{6.023 \times 10^{23} \times 15}{22.4} \\
& =4.033 \times 10^{23} \\
5 \mathrm{~L} \mathrm{~N}_2 & =\frac{6.023 \times 10^{23} \times 5}{22.4} \\
& =1.344 \times 10^{23} \\
0.5 \mathrm{~g} \mathrm{H}_2 & =\frac{6.023 \times 10^{23} \times 0.5}{2} \\
& =1.505 \times 10^{23} \\
10 \mathrm{~g} \mathrm{of}_2 & =\frac{6.023 \times 10^{23} \times 10}{32} \\
& =1.882 \times 10^{23} .
\end{aligned}
$$

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