0.2046 of an organic compound gives 30.4 cm cube of most nitrogen measures at 288 K and 732.7mm pressure calculate the percentage of Nitrogen in substance. aqueous tension at 298 K is 12.7 mm

You are given pressure volume and temperature, use ideal gas equation to calculate moles of nitrogen remember that the data will provide you the moles of nitrogen as pressure exerted by solution is negligible as compared to nitrogen now multiply this molar quantity with 14 to get mass of nitrogen and then finally take the ratio of this amount upon the one which is given in question as original  amount