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In Dumas’ method for estimation of nitrogen, 0.5 gram of an organic compound gave 60 mL of nitrogen collected at 300 K temperature and 715 mm Hg pressure. The percentage composition of nitrogen in the compound (Aqueous tension at 300 K = 15 mm Hg) is %. (1) 12.57 (2) 20.87 (3) 1.257 (4) 18.67

1. 12.57
2. 20.87
3. 1.257
4. 18.67

Correct answer: 12.57

Solution

The correct option is right because the calculation of the percentage of nitrogen is based on the ideal gas law, which accounts for the volume of nitrogen collected, the adjusted pressure (subtracting the aqueous tension), and the mass of the organic compound. This leads to the conclusion that nitrogen constitutes approximately 12.57% of the compound.

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