Verified Solution • 2025–26 Session moderate

QJEEM10Chb527: JEE Main 2010 Chemistry - Class 11 JEEM10Chb527 Solution: 29.5 mg of an organic compound containing nitrogen was digested …

29.5 mg of an organic compound containing nitrogen was digested according to Kjeldahl’s method and the evolved ammonia was absorbed in 20 mL of 0.1 M HCl solution. The excess of the acid required 15 mL of 0.1 M NaOH solution for complete neutralization. The percentage of nitrogen in the compound is

Multiple Choice Options

  • A 59
  • B 47.4
  • C 23.7
  • D 29.5

Step-by-Step Verified Solution

Moles of HClHCl taken =20×0.1×10−3=2×10−3= 20 \times 0.1 \times {10^{ - 3}} = 2 \times {10^{ - 3}}

Moles of HClHCl neutralised by NaOHNaOH solution

=15×0.1×10−3=1.5×10−3= 15 \times 0.1 \times {10^{ - 3}} = 1.5 \times {10^{ - 3}}

Moles of HClHCl neutralised by ammonia

               =2×10−3−1.5×10−3\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 2 \times {10^{ - 3}} - 1.5 \times {10^{ - 3}}

               =0.5×10−3\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 0.5 \times {10^{ - 3}}

%\% of nitrogen =1.4×N×Vw.t.  of  Substan⁡ce×100= {{1.4 \times N \times V} \over {w.t.\,\,of\,\,Subs\tan ce}} \times 100

=1.4×0.5×10−329.5×10−3×100=23.7%= {{1.4 \times 0.5 \times {{10}^{ - 3}}} \over {29.5 \times {{10}^{ - 3}}}} \times 100 = 23.7\%

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