1
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Which one of the following cations gives a chocolate brown precipitate upon addition of aqueous solution of $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ ？
2
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Kjeldahl's method cannot be used for the estimation of nitrogen in which compound?
A
B
C
$\mathrm{C}_6 \mathrm{H}_5-\mathrm{N}=\mathrm{N}-\mathrm{C}_6 \mathrm{H}_5$
D
3
WB JEE 2024
MCQ (Single Correct Answer)
+1
-0.25
The compound that does not give positive test for nitrogen in Lassaigne's test is
A
B
C
D
4
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
To a solution of a colourless efflorescent sodium salt, when dilute acid is added, a colourless gas is evolved along with formation of a white precipitate. Acidified dichromate solution turns green, when the colourless gas is passed through it. The sodium salt is
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