Q101 / 200 · MHT CET - Medical 2026 (24 April Shift 2) · Chemistry
Calculate the number of moles and molecules of chlorine in $4.48\ \text{dm}^3$ of chlorine at STP.
- Correct answerAThe number of mol of chlorine $= 0.2$ and number of molecules $= 1.2044 \times 10^{23}$.
- BThe number of mol of chlorine $= 0.4$ and number of molecules $= 2.4088 \times 10^{23}$.
- CThe number of mol of chlorine $= 0.5$ and number of molecules $= 3.011 \times 10^{23}$.
- DThe number of mol of chlorine $= 0.6$ and number of molecules $= 3.6132 \times 10^{23}$.
Solution
Volume of chlorine gas at STP $= 4.48\ \text{dm}^3$
Molar volume of an ideal gas at STP $= 22.4\ \text{dm}^3\text{mol}^{-1}$
Number of moles of chlorine $= \dfrac{\text{Volume at STP}}{\text{Molar volume}} = \dfrac{4.48}{22.4} = 0.2\ \text{mol}$
Number of molecules of chlorine $= \text{Number of moles} \times N_A$
Number of molecules $= 0.2 \times 6.022 \times 10^{23} = 1.2044 \times 10^{23}$
Answer: The number of mol of chlorine $= 0.2$ and number of molecules $= 1.2044 \times 10^{23}$.
Molar volume of an ideal gas at STP $= 22.4\ \text{dm}^3\text{mol}^{-1}$
Number of moles of chlorine $= \dfrac{\text{Volume at STP}}{\text{Molar volume}} = \dfrac{4.48}{22.4} = 0.2\ \text{mol}$
Number of molecules of chlorine $= \text{Number of moles} \times N_A$
Number of molecules $= 0.2 \times 6.022 \times 10^{23} = 1.2044 \times 10^{23}$
Answer: The number of mol of chlorine $= 0.2$ and number of molecules $= 1.2044 \times 10^{23}$.
Hence, the correct answer is option: 'A'.