Complete combustion of X g of an organic compound gave 0.25 g of CO₂ and 0.12 g of H₂ O . If the % of carbon is 25 % and of hydrogen is 4.89 % , then X = _____ 10⁻³ g. (Nearest integer) (Molar mass of C, H and O are 12, 1 and 16 g mol ⁻¹ respectively.)

Step-by-step solution

Mass of carbon in the compound is calculated from the mass of CO₂ produced: Mass of C = 12 44 mass of CO₂ = 12 44 0.25 = 3 44 g Given that the percentage of carbon in the compound is 25 % : % of C = Mass of C Total mass X 100 25 = 3 44 X 100 X = 3 44 100 25 = 3 44 4 = 3 11 g X 0.2727 g Verifying this using the percentage of hydrogen: Mass of H = 2 18 mass of H₂O = 2 18 0.12 = 1 75 g % of H = 1 75 X 100 = 4.89 X = 100 75 4.89 0.2727 g Thus, X = 272.7 10⁻³ g. Rounding to the nearest integer, the required value is 273