0.50 g of an organic compound was Kjeldahlished. The ammonia evolved w

1.	0.50 g of an organic compound was Kjeldahlished. The ammonia evolved was passed in 50cm3 of IN H2SO4 . The residual acid required 60 cm3 of \(\frac{N}{2}\) NaOH solution. Calculate the percentage of nitrogen in the compound.
Answer» Step 1. Calculation of volume of unused acid Volume of NaOH solution required = 60 cm³ Normality of NaOH solution = \(\frac{1}{2}\)N Normality of H₂SO₄ solution = \(\frac{1}{N}\) Volume of unused acid can be calculated by applying normality equation \(\frac{N_1V_1}{Acid}=\frac{N_1V_1}{Base}\) 1 x V = \(\frac{1}{2}\) x 60 = 30 cm³ Step II. Calculation of volume of acid used Volume of acid added = 50 cm³ Volume of unused acid = 30 cm³ Volume of acid used = (50 – 30) = 20 cm³ Step III. Calculation of percentage of nitrogen mass of compound = 0.05 g Volume of acid used = 20 cm³ Normality of acid used = 1 N Percentage of N = \(\frac{1.4\times Volume\,of\,acid\,used\times Normality\,of\,acid\,used}{Mass\,of\,the\,compound}\) percentage of nitrogen = \(\frac{1.4\times20\times1}{0.50}\) = 56%

0.50 g of an organic compound was Kjeldahlished. The ammonia evolved was passed in 50cm3 of IN H2SO4 . The residual acid required 60 cm3 of \(\frac{N}{2}\) NaOH solution. Calculate the percentage of nitrogen in the compound.

Answer»

Step 1.

Calculation of volume of unused acid

Volume of NaOH solution required = 60 cm³

Normality of NaOH solution = \(\frac{1}{2}\)N

Normality of H₂SO₄ solution = \(\frac{1}{N}\)

Volume of unused acid can be calculated by applying normality equation

\(\frac{N_1V_1}{Acid}=\frac{N_1V_1}{Base}\)

1 x V = \(\frac{1}{2}\) x 60 = 30 cm³

Step II.

Calculation of volume of acid used

Volume of acid added = 50 cm³

Volume of unused acid = 30 cm³

Volume of acid used = (50 – 30) = 20 cm³

Step III.

Calculation of percentage of nitrogen

mass of compound = 0.05 g

Volume of acid used = 20 cm³

Normality of acid used = 1 N

Percentage of N = \(\frac{1.4\times Volume\,of\,acid\,used\times Normality\,of\,acid\,used}{Mass\,of\,the\,compound}\)

percentage of nitrogen = \(\frac{1.4\times20\times1}{0.50}\) = 56%