JEE Main Chemistry question
In Kjeldahl's method, ammonia from 5 g of food neutralizes 30 cm³ of 0.1 acid. The percentage of nitrogen in the food is
Answer: 0.84%
Solution
Moles acid = 30 × 0.1/1000 = 0.003 mol = mol NH₃ = mol N. Mass N = 0.003 × 14 = 0.042 g. %N = (0.042/5) × 100 = 0.84%.