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0.45 gm of an organic compound gave on combustion 0.792 gm of CO 2 and 0.324 gm of water. 0.24 gm of the same substance was Kjeldahlised and the ammonia liberated was absorbed in 50.0 ml of M/8 H 2 SO 4 . The excess acid required 77.0 ml of N/10 NaOH for complete neutralisation. Calculate the empirical formula of the compound.

Options

  1. AH 4 C 2 N 8 O
  2. BC 2 H 4 N 8 O
  3. CC 4 H 8 N 2 O
  4. DC 2 N 2 H 4 O

Correct answer

C. C 4 H 8 N 2 O

Step-by-step solution

Calculation of the percentage composition : i) Percentage of carbon = 1 2 4 4 × Mass of CO 2 Produced Mass of substance taken × 1 0 0 = 1 2 4 4 × 0 . 7 9 2 0 . 4 5 × 1 0 0 = 4 8 . 0 ii) Percentage of hydrogen = 2 1 8 × Mass of H 2 O produced Mass of substance taken × 1 0 0 = 2 1 8 × 0 . 3 2 4 0 . 4 5 × 1 0 0 = 8 . 0 iii) Percentage of nitrogen mEq. of H 2 SO 4 = 5 0 × M 8 × 2 = 1 2 . 5 mEq. of NaOH = 7 2 × 1 1 0 × 1 = 7 . 7 Excess of H 2 SO 4 u

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