In the estimation of nitrogen by Kjeldahl's method, 0.7 g of an organic compound was digested and the evolved ammonia was passed into 50 mL of 0.25 M H ₂ SO ₄ . The residual acid required 30 mL of 0.5 M NaOH for complete neutralization. The

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In the estimation of nitrogen by Kjeldahl's method, 0.7 g of an organic compound was digested and the evolved ammonia was passed into 50 mL of 0.25 M H ₂ SO ₄ . The residual acid required 30 mL of 0.5 M NaOH for complete neutralization. The percentage of nitrogen in the compound is _______.

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Correct answer: 20

The total milliequivalents of H ₂ SO ₄ taken initially: meq of H ₂ SO ₄ = Volume (mL) Molarity n-factor meq of H ₂ SO ₄ = 50 0.25 2 = 25 meq The milliequivalents of NaOH used for back-titration to neutralize the residual acid: meq of NaOH = Volume (mL) Molarity n-factor meq of NaOH = 30 0.5 1 = 15 meq The milliequivalents of H ₂ SO ₄ that reacted with the evolved ammonia: meq of NH ₃ = Initial meq of H ₂ SO ₄ - meq of NaOH used meq of NH ₃ = 25 - 15 = 10 meq The percentage of nitrogen in the organic compound is giv

In the estimation of nitrogen by Kjeldahl's method, 0.7 g of an organic compound was digested and the evolved ammonia was passed into 50 mL of 0.25 M H ₂ SO ₄ . The residual acid required 30 mL of 0.5 M NaOH for complete neutralization. The percentage of nitrogen in the compound is _______.

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