Assertion (A) & Reason (B) MCQ

MCQ 11 Mark

Assertion $(A): \ce{(CH_3)_3C-O-CH_3}$ gives $\ce{(CH_3)_3C-I}$ and $\ce{CH_3OH}$ on treatment with $HI.$
Reason $(R):$ The reaction occurs by $S_N1$ mechanism.

✓
Both $A$ and $R$ are true and $R$ is the correct explanation of $A.$
B
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
C
$A$ is true but $R$ is false.
D
$A$ is false but $R$ is true.

Answer

Correct option: A.

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

$\ce{(CH_3)_3C-O-CH_3}$ gives $\ce{(CH_3)_3C-I}$ and $\ce{CH_3OH}$ on treatment with $\ce{HI}.$ The reaction occurs by $S_N1$ mechanism.

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MCQ 21 Mark

Assertion (A): Alkylbenzene is not prepared by Friedel-Crafts alkylation of benzene.
Reason (R): Alkyl halides are less reactive than acyl halides.

A
Both A and R are true and R is the correct explanation of A.
B
Both A and R are true but R is not the correct explanation of A.
✓
A is true but R is false.
D
A is false but R is true.

Answer

Correct option: C.

A is true but R is false.

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MCQ 31 Mark

Assertion $(A):$ Oximes are less acidic than hydroxyl amine.
Reason $(R):$ Oximes of aldehydes and ketones show geometrical isomerism.

A
Both $A$ and $R$ are true and $R$ is the correct explanation of $A.$
✓
Both $A$ and $R$ are true but $R$ is not the correct explanation of $A.$
C
$A$ is true but $R$ is false.
D
$A$ is false but $R$ is true.

Answer

Correct option: B.

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

Oximes are more acidic because, there is a delocalisation of $\pi$ electrons $($i.e. resonance$)$ and it stabilises it and its conjugate acid. But no such resonance exists in hydroxyl amine base $\ce{(NH_2O^-)}.$

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MCQ 41 Mark

Assertion (A): Vitamin C cannot be stored in our body.
Reason (R): Vitamin C is fat soluble and is excreted from the body in urine.

A
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
B
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
✓
Assertion (A) is true, but Reason (R) is false.
D
Assertion (A) is false, but Reason (R) is true.

Answer

Correct option: C.

Assertion (A) is true, but Reason (R) is false.

(c) Assertion (A) is true, but Reason (R) is false.
Explanation: In a tetrapeptide, there are four amino acids connected by three peptide bonds

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Chemistry Assertion (A) & Reason (B) MCQ

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