Explain why chlorine but not nitrogen in hydroxylamine hydrochloride `(NH_(2)OH*HCI)`can be detected by Lassaigne's test.

Explanation

Hydroxylamine hydrochloride `(NH_(2)OH*HCI)` contains nitrogen but does not contain carbon as an element. So, on fusion with metallic sodium it cannot form sodium cyanide. Cyanide ion is essential to produce prussian blue. Thus nitrogen cannot be detected by Lassaigne's test. However hydroxylamine hydrochloride contains chlorine as an element and so on fusion with Na, it forms NaCI. Thus, chlorine can be detected by Lassaigne's test.