1
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Lassaigne's test for the detection of nitrogen fails in

A

$\mathrm{NH}_2-\mathrm{NH}_2 \mathrm{HCl}$

B

$\mathrm{NH}_2 \mathrm{CONHNH}_2 \mathrm{HCl}$

C

$\mathrm{C}_6 \mathrm{H}_5 \mathrm{NHNH}_2 \mathrm{HCl}$

D

$\mathrm{NH}_2 \mathrm{CONH}_2$

2
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

$\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ for a reaction are $35.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $83.6 \mathrm{~J} \mathrm{~K}^{-1}$ respectively. Assuming that $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ do not vary with temperature, the reaction is spontaneous when:

A

$\mathrm{T}<425 \mathrm{~K}$

B

$\mathrm{T}<350 \mathrm{~K}$

C

$\mathrm{T}>425 \mathrm{~K}$

D

$T>298 \mathrm{~K}$

3
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

When the initial concentration of a zero order reaction is doubled, the half-life of the reaction is:

A

doubled

B

not changed

C

tripled

D

halved

4
COMEDK 2026 Morning Shift
MCQ (Single Correct Answer)
+1
-0

The secondary structure of protein consists of:

A

A long chain of amino acids linked with each other in a specific sequence

B

A folding of the polypeptide chains which exists as fibrous and globular

C

A long polypeptide chain which exists $\alpha$-helix and $\beta$-pleated sheet structure

D

Two or more polypeptide chains which exist as sub-units