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

$\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ on heating with aqueous NaOH gives $\_\_\_\_$

A

$\mathrm{Cr}(\mathrm{OH})_2$

B

$\mathrm{Cr}(\mathrm{OH})_3$

C

$\mathrm{CrO}_4{ }^{2-}$

D

$\mathrm{CrO}_3$

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

In the photoelectric emission, the energy of the emitted electron is:

A

greater than the energy of the incident photon

B

smaller than the energy of the incident photon

C

same as that of the incident photon

D

proportional to the intensity of the incident photon

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

Identify the name of the reaction involved in conversion of $A \rightarrow B$ and name the compound $B$.

$$ \mathrm{CH}_3 \mathrm{CN} \xrightarrow[\mathrm{H}_2 \mathrm{O}]{\mathrm{H}^{+}} \mathrm{A}-\xrightarrow[\mathrm{H}^{+} / \mathrm{H}_2 \mathrm{O}]{\mathrm{Cl}_2 / \text { Red Phosphorous }} \mathrm{B} $$

A

Kolbe's reaction, Ethanoic acid

B

Esterification, methyl ethanoate

C

Hell-Volhard-Zelinsky reaction, 2-chloro-ethanoic acid

D

Riemer-Tiemann reaction, 1-chloro-ethanoic acid

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

The Crystal Field Stabilisation energy of (i) $\left[\mathrm{CoF}_6\right]^{3-}$ and (ii) $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$ are ⋯and ⋯⋯ respectively.

A

(i) $-2.8 \Delta_0$         (ii) $-2.4 \Delta_0$

B

(i) $2.8 \Delta_0$        (ii) $2.4 \Delta_0$

C
(i) $-0.6 \Delta_0$        (ii) $0.4 \Delta_0$
D
(i) $-0.4 \Delta_0$         ii) $0 \Delta_0$