1
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Identify the two incorrect electrochemical reactions shown as taking place in the given cells at the respective electrodes.

Cell Electrode Reaction
Lead-Storage Cell Cathode $\mathrm{Pb}+2 \mathrm{SO}_4{ }^{2-}+4 \mathrm{H}^{+}+2 \mathrm{e}^{-} \rightarrow \mathrm{PbSO}_4+2 \mathrm{H}_2 \mathrm{O}+\mathrm{SO}_2$
Leclanche Cell Cathode $\mathrm{MnO}_2+\mathrm{NH}_4^{+}+2 \mathrm{e}^{-} \rightarrow \mathrm{MnO}+\mathrm{OH}+\mathrm{NH}_3$
Mercury Cell Anode $\mathrm{Zn} / \mathrm{Hg}+2 \mathrm{OH}^{-} \rightarrow \mathrm{ZnO}(\mathrm{s})+\mathrm{H}_2 \mathrm{O}+2 \mathrm{e}^{-}$
Fuel Cell Cathode $\mathrm{O}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}+4 \mathrm{e}^{-} \rightarrow 4 \mathrm{OH}^{-}$

A
C & D
B
A & C
C
B & D
D
A & B
2
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0
Choose the correct statement.
A
The plot of $[A]$ versus time " $t$ " for a zero order reaction is a horizontal line parallel to the $x$-axis which represents " $t$ "
B
For a first order reaction the time taken for $3 / 4^{\text {th }}$ completion is 2 times the half-life period.
C
For a second order reaction the rate of reaction with respect to reactant becomes 27 times when its concentration is tripled.
D
Molecularity of a chemical reaction is always greater than order of the reaction.
3
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Consider the following reaction

$$\text { Propyne }+\mathrm{CH}_3 \mathrm{MgBr} \xrightarrow{\text { dry ether }} \mathbf{X}$$

Identify ' X ' from the following.

A
But-2-yne
B
Propane
C
Methane
D
But-2-ene
4
COMEDK 2025 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Match the IUPAC names in Column II with the correct structures given in Column I.

Structures of compounds IUPAC name
A COMEDK 2025 Evening Shift Chemistry - IUPAC Nomenclatures Question 1 English 1 P 1-Bromomethyl-3-(2,2-dimethylpropyl)benzene
B COMEDK 2025 Evening Shift Chemistry - IUPAC Nomenclatures Question 1 English 2 Q 1-Bromo-4-(1-methylethyl)benzene
C COMEDK 2025 Evening Shift Chemistry - IUPAC Nomenclatures Question 1 English 3 R 1-Bromo-2-(1-methylpropyl)benzene
D COMEDK 2025 Evening Shift Chemistry - IUPAC Nomenclatures Question 1 English 4 S 1-Bromo-4-(2-methylpropyl)benzene

A
$\mathrm{A}=\mathrm{R} \quad \mathrm{B}=\mathrm{P} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{Q}$
B
$\mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{Q} \quad \mathrm{D}=\mathrm{P}$
C
$\mathrm{A}=\mathrm{Q} \quad \mathrm{B}=\mathrm{P} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{R}$
D
$\mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{P} \quad \mathrm{D}=\mathrm{Q}$
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