Given below are two statements :
Statement I: In 'Lassaigne's Test, when both nitrogen and sulphur are present in an organic compound, sodium thiocyanate is formed.
Statement II : If both nitrogen and sulphur are present in an organic compound, then the excess of sodium used in sodium fusion will decompose the sodium thiocyanate formed to give NaCN and .
In the light of the above statements, choose the most appropriate answer from the options given below :
Statement I: In 'Lassaigne's Test, when both nitrogen and sulphur are present in an organic compound, sodium thiocyanate is formed.
Statement II : If both nitrogen and sulphur are present in an organic compound, then the excess of sodium used in sodium fusion will decompose the sodium thiocyanate formed to give NaCN and .
In the light of the above statements, choose the most appropriate answer from the options given below :
- (A)Both Statement I and Statement II are correct.✓ Correct
- (B)Both Statement I and Statement II are incorrect.
- (C)Statement I is correct but Statement II is incorrect.
- (D)Statement I is incorrect but Statement II is correct.
Answer: (A)
Solution
In Lassaigne's sodium-fusion test an organic compound containing both nitrogen and sulphur gives sodium thiocyanate, since nitrogen, carbon and sulphur combine with sodium as ; this is why such compounds give the blood-red ferric thiocyanate, so the first statement is correct. The amount of sodium decides what survives: when sodium is present in excess, as it usually is during fusion, it reduces the thiocyanate and splits it into sodium cyanide and sodium sulphide, , after which nitrogen and sulphur are detected separately. The second statement describes this correctly, so both statements are correct.
JEE Main · 2022 · 26 Jun 2022 · Shift 1 · Single correct option