Basics of Organic Reaction Mechanism MCQs Question and Answer in Engineering Chemistry

41

Among the carboxylic acid shown below, the ones that exhibit stereoisomerism and also form, cyclic anhydrides on heating are
I. HOOCCH(CH₃)CH₂CH₂COOH
II. HOOCCH(C₃H₇)COOH
III. HOOCCH(C₂H₅)CH₂COOH
IV. HOOCC(CH₃)(C₂H₅)COOH

A) I and II B) I and III C) II and III D) II and IV

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Answer & Solution

Answer: Option B

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42

Match the following compounds with their respective classes
Basics of Organic Reaction Mechanism mcq question image

A) I:steroid; II:terpenoid; III:alkaloid; IV:DNA base B) I:terpenoid; II:steroid; III:alkaloid; IV:DNA base C) I:terpenoid; II:steroid; III:DNA base; IV:alkaloid D) I:steroid; II:terpenoid; III:DNA base; IV:alkaloid

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Answer & Solution

Answer: Option B

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43

The sequence of an mRNA molecule produced from a DNA template strand with the composition 5'-AGCTACACT-3' is

A) 5'-AGUGUAGCU-3' B) 5'-UCGAUGUGA-3' C) 5'-AGTGTAGCT-3' D) 5'-TCGATGTGA-3'

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Answer & Solution

Answer: Option B

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44

Pyrrole + PhMgBr → E + F
E + MeCl → G + H
F + MeCl → no reaction without a catalyst
Basics of Organic Reaction Mechanism mcq question image

The structure of products E - H respectively are

A) 3, 2, 6, 7 B) 4, 5, 6, 1 C) 3, 4, 5, 2 D) 3, 2, 4, 5

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Answer & Solution

Answer: Option A

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45

The mono protonation of adenine (X) in acidic solution mainly occurs at
Basics of Organic Reaction Mechanism mcq question image

A) position 1 B) position 2 C) position 3 D) position 4 or 5

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Answer & Solution

Answer: Option D

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46

The molecules(s) that exist as meso structure (s)
Basics of Organic Reaction Mechanism mcq question image

is/are

A) only M B) both K and L C) only L D) only K

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Answer & Solution

Answer: Option B

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47

Three molecular ionic states, P-R are possible for the amino acid histidine. Identify the correct choice of pH values, respectively for the observation of the ionic states P-R.
Basics of Organic Reaction Mechanism mcq question image

A) P at pH 1; Q at pH 12; R at pH 7 B) P at pH 7; Q at pH 1; R at pH 12 C) P at pH 12; Q at pH 7; R at pH 1 D) P at pH 12; Q at pH 1; R at pH 7

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Answer & Solution

Answer: Option A

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48

In allene, hybridization of the central and terminal carbons respectively, are

A) sp² and sp² B) sp² and sp³ C) sp and sp² D) sp and sp³

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Answer & Solution

Answer: Option C

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49

Benzene cannot be iodinated with $${I_2}$$ directly. However, in presence of oxidants such as HNO₃, iodination is possible. The electrophiles formed in the case is

A) $$\left[ {{I^ + }} \right]$$ B) $$\left[ {{I^ - }} \right]$$ C) $${\left[ {\mathop I\limits^{ + \delta } ...\mathop O\limits^{ + \delta } {H_2}} \right]^ + }$$ D) $${\left[ {\mathop I\limits^{ + \delta } ...\mathop O\limits^{ - \delta } {H_2}} \right]^ + }$$

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Answer & Solution

Answer: Option A

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50

In electrophilic aromatic substitution reactions, nitro group is meta-directing because the nitro group

A) increases electron density at meta-position B) increases electron density at ortho and para-positions C) decreases electron density at meta-position D) decreases electron density at ortho and para-positions

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Answer & Solution

Answer: Option D

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