MolSynapsequestion bank
MolSynapse / Question bank / Structural Identification and Practical Organic Chemistry / Estimation of elements: Lassaigne, Kjeldahl, Carius
JEE Advanced levelOne or more correct optionsDifficulty 3 of 3si196

Benzenesulfonamide, , is fused with excess sodium (so that thiocyanate is not formed) and the sodium extract is tested. Which observations are correct?

  1. APrussian blue is obtained on adding , boiling, and acidifying.
  2. BA violet colour is obtained with sodium nitroprusside.
  3. CA blood-red colour is obtained on adding acidified .
  4. DA white precipitate soluble in dilute ammonia is obtained with after boiling with .

Answer: A, B

The compound contains N and S but no halogen. With excess sodium the extract has and , giving Prussian blue (A) and the violet nitroprusside colour (B). No is present, so no blood-red colour (C). There is no chloride, so no white (D).
Practice Structural Identification and Practical Organic Chemistry More on Estimation of elements: Lassaigne, Kjeldahl, Carius
Previous questionNext question

More questions on Estimation of elements: Lassaigne, Kjeldahl, Carius