In Kjeldahl's method for the estimation of nitrogen, 0.5 g of an organic compound was digested and the evolved ammonia was completely neutralized by a solution of 0.5 M H ₂ SO ₄ . If the percentage of nitrogen in the given organic compound is 42 % , the volume of 0.5 M H ₂ SO ₄ required is _______ mL .

Step-by-step solution

The formula for the percentage of nitrogen in Kjeldahl's method is given by: % N = 1.4 N_ acid V_ acid W where N_ acid is the normality of the acid, V_ acid is the volume of the acid in mL , and W is the mass of the organic compound. Given: Mass of organic compound, W = 0.5 g Percentage of nitrogen = 42 % Molarity of H ₂ SO ₄ = 0.5 M The basicity (n-factor) of H ₂ SO ₄ is 2 . Normality of H ₂ SO ₄ , N_ acid = Molarity 2 = 0.5 2 = 1 N Substituting the values into the formula: 42 = 1.4 1 V_ acid 0.5 42 0.5 = 1.4 V_ a