Qualitative Organic Analysis

Step 1: Using the ideal gas law.
At S.T.P., 1 mole of gas occupies 22.4 L. The volume of nitrogen gas is given as 22.4 mL (which is 0.0224 L). The number of moles of nitrogen can be calculated as: Step 2: Calculating the mass of nitrogen.
The molecular weight of nitrogen (N) is 14 g/mol, and the total nitrogen mass in the sample is: Step 3: Calculating percentage of nitrogen.
The percentage of nitrogen in the sample is: Step 4: Conclusion.
The correct answer is (B) 7.0%, as it represents the percentage of nitrogen in the compound.