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 $$Na_2S$$.
In the light of the above statements, choose the most appropriate answer from the options given below

We need to evaluate two statements about Lassaigne's Test when both nitrogen and sulphur are present in an organic compound.

Evaluate Statement I.

Statement I: When both nitrogen and sulphur are present in an organic compound, sodium thiocyanate (NaSCN) is formed during sodium fusion.

This is correct. When an organic compound containing both N and S is fused with sodium metal:

$$Na + C + N + S \rightarrow NaSCN$$

Sodium thiocyanate is formed instead of NaCN and Na$$_2$$S separately.

Evaluate Statement II.

Statement II: Excess sodium decomposes sodium thiocyanate to give NaCN and Na$$_2$$S.

This is correct. When excess sodium is used in the fusion:

$$NaSCN + 2Na \rightarrow NaCN + Na_2S$$

The excess sodium breaks down the thiocyanate, allowing both nitrogen (as NaCN) and sulphur (as Na$$_2$$S) to be detected separately in subsequent tests. This is why excess sodium is recommended when both elements are suspected to be present.

Conclusion.

Both Statement I and Statement II are correct.

The correct answer is Option A: Both Statement I and Statement II are correct.