Q91 / 200 · NEET 2012 (Screening) · Chemistry

Which of the statements is not true?

  • A
    On passing $\mathrm{H}_2 \mathrm{~S}$ through acidified $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution, a milky colour is observed
  • Correct answer
    B
    $\mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7$ is preferred over $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ in volumetric analysis
  • C
    $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution in acidic medium is orange
  • D
    $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution becomes yellow on increasing the $\mathrm{pH}$ beyond 7

Solution

Being hygroscopic, sodium dichromate, $\mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7$ cannot be used in volumetric analysis. All other given statements are true.

Hence, the correct answer is option: 'B'.

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