Kjeldahl method is commonly used to determine the percentage of nitrogen in organic compounds. In this method, the organic compound is first digested with concentrated sulfuric acid in the presence of a catalyst such as copper or mercury. The nitrogen in the compound is converted to ammonium sulfate, which is then treated with excess sodium hydroxide to convert it to ammonia gas. The evolved ammonia is then absorbed in a known volume of acid, and the excess acid is titrated with a standard solution of sodium hydroxide.

Given data:
Mass of organic compound = 0.4422 g
Volume of 0.5 M H2SO4 = 50 mL
Volume of 0.25 M NaOH used = 131 mL

To determine the percentage of nitrogen in the compound, we need to calculate the amount of nitrogen present in the compound and then calculate its percentage.

1. Calculating the amount of nitrogen:
We know that 1 mole of nitrogen reacts with 1 mole of H2SO4 and produces 2 moles of NaOH. From the volume of H2SO4 and NaOH used, we can calculate the number of moles of H2SO4 and NaOH used.

Moles of H2SO4 used:
Moles = Volume (in L) x Concentration (in mol/L)
Moles of H2SO4 = 50 mL x 0.5 mol/L = 0.025 mol

Moles of NaOH used:
Moles = Volume (in L) x Concentration (in mol/L)
Moles of NaOH = 131 mL x 0.25 mol/L = 0.03275 mol

From the balanced chemical equation, we can see that 2 moles of NaOH react with 1 mole of nitrogen. Therefore, the moles of nitrogen in the compound can be calculated as follows:

Moles of nitrogen = 0.03275 mol/2 = 0.016375 mol

2. Calculating the mass of nitrogen:
The molar mass of nitrogen (N) is 14.01 g/mol. Therefore, the mass of nitrogen in the compound can be calculated as follows:

Mass of nitrogen = Moles of nitrogen x Molar mass of nitrogen
Mass of nitrogen = 0.016375 mol x 14.01 g/mol = 0.22930125 g

3. Calculating the percentage of nitrogen:
The percentage of nitrogen is calculated by dividing the mass of nitrogen by the mass of the organic compound and multiplying by 100.

Percentage of nitrogen = (Mass of nitrogen / Mass of organic compound) x 100
Percentage of nitrogen = (0.22930125 g / 0.4422 g) x 100 = 51.85%

Therefore, the percentage of nitrogen in the compound is approximately 51.85%.

In summary:
- Mass of nitrogen in the compound = 0.22930125 g
- Percentage of nitrogen in the compound = 51.85%