Qualitative analysis of organic compounds is performed by Lassaigne's test by fusion with metallic sodium, by which the covalent compounds are converted into ionic compounds. Extra elements like `N,S,P` and halogens are detected by their usual tests.
Q. Which of the following will give blood-red colour in lassaigne's test for nitrogen

Options

A. `NO_2^(c-)`
B. `Coverset(c-)N`
C. `CNS^(c-)`
D. `S^(2-)`

Answer

A

Explanation

In lassaigen's test, N is converted to `CN^(c-)` ion, S is converted to `S^(2-)` ion, N and S are converted to `CNS^(c-)` ions, halogens are converted to halide ion `(X^(c-)`), P is converted to `PO_4^(3-)` ions. So `NO_3^(c-)` is never present is Lassaigne's extract. Hence the answer is (a).