1
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

What is the quantity of charge, in Faraday units, required for the reduction of 3.5 moles of $$\mathrm{Cr}_2 \mathrm{O} 7^{2-}$$ in acid medium?

A
6.0
B
10.5
C
21.0
D
3.0
2
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

A dry cell consists of a moist paste of $$\mathrm{NH}_4 \mathrm{Cl}$$ and $$\mathrm{ZnCl}_2$$ contained in a $$\mathrm{Zn}$$ casing which encloses a Carbon rod surrounded by black $$\mathrm{MnO}_2$$ paste. What is the role of $$\mathrm{ZnCl}_2$$ in it?

A
It prevents pressure being developed in the cell due to $$\mathrm{NH}_3$$ gas formation.
B
It serves as cathode thus permitting Carbon rod to act as anode.
C
It acts as the anode while Carbon rod acts as the cathode.
D
It keeps the contents dry and prevents leakage of electrolyte.
3
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Compounds $$\mathrm{A}$$ and $$\mathrm{B}$$, having the same molecular formula $$(\mathrm{C}_4 \mathrm{H}_8 \mathrm{O})$$, react separately with $$\mathrm{CH}_3 \mathrm{MgBr}$$, followed by reaction with dil. $$\mathrm{HCl}$$ to form compounds $$\mathrm{X}$$ and $$\mathrm{Y}$$ respectively. Compound $$\mathrm{Y}$$ undergoes acidic dehydration in presence of Conc. $$\mathrm{H}_2 \mathrm{SO}_4$$ much more readily than $$\mathrm{X}$$. Compound $$\mathrm{Y}$$ also reacts with Lucas reagent, much more readily than $$\mathrm{X}$$, with appearance of turbidity. Identify $$\mathrm{X}$$ and $$\mathrm{Y}$$.

A
$$ \mathrm{X}=\text { Pentan }-1-\mathrm{ol} \quad \mathrm{Y}=\text { Pentan }-2-\mathrm{ol} $$
B
$$ \mathrm{X}=\text { Butan-2-ol } \quad \mathrm{Y}=\text { 2-Methylpropan-2-ol } $$
C
$$ \mathrm{X}=\text { Pentan-1-ol } \quad \mathrm{Y}=2-\text { Methylpentan-2-ol } $$
D
$$ \mathrm{X}=\text { Pentan-2-ol } \quad \mathrm{Y}=2 \text {-Methylbutan-2-ol } $$
4
COMEDK 2024 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Match the names of reactions given in Column I with the appropriate reactions given in Column II.

No. Name of reaction No. Equations representing reactions
(A) Sandmeyer (P) $$
2 \mathrm{C}_6 \mathrm{H}_5 \mathrm{Cl}+\mathrm{Na} \text { (dry ether) } \rightarrow \text { Diphenyl. }
$$
(B) Fittig (Q) $$
\mathrm{CH}_3-\mathrm{CHBr}-\mathrm{CH}_3+\mathrm{AgF} \rightarrow \mathrm{CH}_3-\mathrm{CHF}-\mathrm{CH}_3+\mathrm{AgBr}
$$
(C) Swarts (R) $$
\mathrm{CH}_3-\mathrm{CH}_2-\mathrm{Br}+\mathrm{Nal} \text { ( Acetone) } \rightarrow \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{I}+\mathrm{NaBr}
$$
(D) Finkelstein (S) $$
\mathrm{C}_6 \mathrm{H}_5 \mathrm{~N}_2+\mathrm{Cl}-+\mathrm{Cu}_2 \mathrm{Br}_2 / \mathrm{HBr} \rightarrow \mathrm{C}_6 \mathrm{H}_5 \mathrm{Br}+\mathrm{N}_2
$$

A
$$ \mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{P} \quad \mathrm{C}=\mathrm{Q} \quad \mathrm{D}=\mathrm{R} $$
B
$$ \mathrm{A}=\mathrm{Q} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{P} $$
C
$$ \mathrm{A}=\mathrm{S} \quad \mathrm{B}=\mathrm{R} \quad \mathrm{C}=\mathrm{Q} \quad \mathrm{D}=\mathrm{P} $$
D
$$ \mathrm{A}=\mathrm{R} \quad \mathrm{B}=\mathrm{P} \quad \mathrm{C}=\mathrm{S} \quad \mathrm{D}=\mathrm{Q} $$
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12