JEE Main levelSingle correct optionDifficulty 2 of 3eq207
In Kjeldahl's method, the ammonia from 0.600g of an organic compound is absorbed in 40.0mL of 0.100MHX2SOX4. The excess acid needs 18.0mL of 0.200MNaOH. Taking N=14, the percentage of nitrogen in the compound is:
A0.93%
B5.13%
C10.27%
D18.67%
Answer: C
Acid taken =40.0×0.100×2=8.0 meq; excess =18.0×0.200=3.6 meq; acid used by NHX3=4.4 meq =4.4 mmol of NHX3 (one N each). Mass of N =4.4×14=61.6 mg. Percentage =61.6/600×100=10.27%.