In Dumas’ method for estimation of nitrogen \(0.4\mathrm{g}\) of an organic compound gave \(60\mathrm{mL}\) of nitrogen …
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In Dumas’ method for estimation of nitrogen \(0.4\mathrm{g}\) of an organic compound gave \(60\mathrm{mL}\) of nitrogen collected at \(300\mathrm{K}\) temperature and \(715\mathrm{mm}\) Hg pressure. The percentage composition of nitrogen in the compound is
(Given : Aqueous tension at \(300\mathrm{K}=15\mathrm{mm}\mathrm{Hg}\))
[JEE Main 2025, 3 Apr (Shift 2)]
✓ Correct answer: a)
\(15.71%\)
Explanation
Pressure of N₂ gas evolved
\(=715−15=700\text{ mm Hg}\) \(=\frac{700}{760}\text{ atm}\)Moles of N₂ evolved:
\(n=\frac{PV}{RT}\) \(=\frac{700\times 60\times {10}^{−3}}{760\times 0.0821\times 300}\) \(=0.0022\text{ mol}\)Mass of N₂ evolved:
\(=0.0022\times 28=0.063\text{ g}\)Weight percentage of nitrogen in the compound:
\(\mathrm{%}N=\frac{\text{wt. of nitrogen}}{\text{wt. of compound}}\times 100\)% \(=\frac{0.063}{0.4}\times 100\) = 15.71%Practice more JEE Chemistry PYQs
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