Some Basic Concepts of Chemistry - Result Question 29
30. The largest number of molecules is in
(1979, 1M)
(a) 36 g of water
(b) 28 g of CO
(c) 46 g of ethyl alcohol
(d) 54 g of nitrogen pentaoxide $\left(\mathrm{N}_2 \mathrm{O}_5\right)$
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Answer:
Correct Answer: 30. (a)
Solution:
- Number of molecules present in 36 g of water
$=\frac{36}{18} \times N_A=2 N_A$
Number of molecules present in 28 g of $\mathrm{CO}=\frac{28}{28} \times N_A=N_A$
Number of molecules present in 54 g of $_2 \mathrm{O}_5=\frac{54}{108} \times N_A=0.5 N_A$
Here, $N_A$ is Avogadro’s number. Hence, 36 g of water contain the largest $\left(2 N_A\right)$ number of molecules.
BETA
