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

The statements given below contains assertion and reason. Choose the correct option

Assertion (A): Cr, Mo and W possess the highest melting point in their respective series of elements.

Reason (R): Cr, Mo and W have stable half-filled electrons in the 'd' shell resulting in strong metallic bonding.

A

A is true but R is false

B

Both $A$ and $R$ are true, $R$ is the correct explanation of $A$

C

Both $A$ and $R$ are true but $R$ is not the correct explanation of $A$

D

A is false but R is true

2
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

$\mathrm{CrO}_3$

3
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

4
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