Class 11 Chemistry - Chapter Organic Chemistry Some Basic Principles and Techniques NCERT Solutions | A sample of 0.50 g of an organic compoun
A sample of 0.50 g of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in 50 mL of 0.5 M H2SO4. The residual acid required 60 mL of 0.5 M solution of NaOH for neutralisation. Find the percentage composition of nitrogen in the compound.
Given that, total mass of organic compound = 0.50 g
60 mL of 0.5 M solution of NaOH was required by residual acid for neutralisation.
60 mL of 0.5 M NaOH solution = 60/2 mL of 0.5M H2SO4 = 30 mL of 0.5 M H2SO4
∴Acid consumed in absorption of evolved ammonia is (50-30) mL = 20 mL
Again, 20 mL of 0.5 MH2SO4 = 40 mL of 0.5 MNH3
Also, since 1000 mL of 1 MNH3 contains 14 g of nitrogen,
∴ 40 mL of 0.5 M NH3 will contain 14x40x0.5 / 1000 = 0.28 g of N
Therefore, percentage of nitrogen in 0.50 g of organic compound 0.28/0.50 x 100 = 56 %
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