1.4g of an organic compound was digested according to Kjeldahl's method and the ammonia evolved was absorbed in 60mL of M/10 H2SO4 solution. The excess sulphuric acid required 20mL of M/10 NaOH solution for neutralization. The percentage of nitrogen in the compound is:

Out of 60mL of M/10 H2SO4, 20mL will be neutralized with 20mL of M/10 NaOH. Hence, 60 - 20 = 40mL of M/10 H2SO4 will be neutralized with ammonia. This will be equal to 80mL ammonia.

1000mL of 1 M ammonia corresponds to 14g.

80mL of M/10 ammonia will correspond to (80/1000) x (1/10) x 14 = 0.112g nitrogen

Thus, 1.4g of organic compound contains 0.112g nitrogen.

Hence, 100g of organic compound will contain (0.112/1.4) x 100 = 8g nitrogen

Hence, the per cent of nitrogen in the organic compound is 8