Q. Which of the organic compounds will give red colour in Lassaigne test?
A) $NaCNS$
B) $S$
$||$
$NH_{2} - C - NH_{2}$
C) $O$
$||$
$NH_{2} - C - NH_{2}$
D) None of these
Explanation
(b)
In the lassaigne test, if organic compound consists of both N and S, then a red colour is obtained on adding aqueous
$S$
$||$
$FeCl_{3}$ To sodium extract. $NH_{2} - C - NH_{2}$ contains both N and S hence, it will give red colour in Lassaigne test
$NaCNS + FeCl_{3} \longrightarrow \left\lbrack Fe(SCN) \right\rbrack Cl_{2} + NaCl$
Blood red colour
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.