Question

0.255 g of an organic nitrogenous compound was kjeldahlised and the ammonia evolved was absorbed

in 50cm3

of N/10 H2SO4. The excess acid required to 10cm3

of N/5 NaOH. Calculate the percentage

of nitrogen in the given compound.​

Answer 1

Percentage of N2 in the given compound = 56%

Explanation:

Mass of organic compound = 0.255 g

Unused acid required = 50ml. N/10. NaOH

50ml. N/10. NaOH = 50ml. N/10. N + H2SO4

  = 25 ml N/5. N2SO4.

Acid used for absorption of Ammonia = (50-10) ml H2SO4.

  = 40ml N/5. H2SO4.

Percentage of nitrogen = 1.4 * N1 * V / W  

 = 1.4 * 1/5 * 40 /0.2

  = 56

Percentage of N2 in the given compound = 56%

Answer 2

Answer:

Mass of organic compound = 0.255 g

Unused acid required = 50ml. N/10. NaOH

50ml. N/10. NaOH=50mI.N/10. N + H2SO4

= 25 ml N/5. N2SO4.

Acid used for absorption of Ammonia = (50-10) ml H2SO4.

= 40ml N/5. H2SO4.

Percentage of nitrogen = 1.4 * N1 * V/W = 1.4 * 1/5 * 40 /0.2

= 56.