JEE Questions for Chemistry Haloalkanes And Haloarenes Quiz 6 - MCQExams.com

Weaker the base better the leaving group. Since the basicities decrease in the order : OMe (II) > OAc (I) > OSO₂Me (III) >OSO₂CF₃(IV), therefore, the order of leaving group ability decreases in the reverse order, i.e, IV > III > I > II.

Only 1-phenylethanol (CH₃CHOHC₆H₅) has the grouping CH₃CHOH and hence gives +ve iodoform test.

Reactivity decreases as the number of NO₂ groups at o- and p-position w.r.t. to Br decreases. m-Nitrobromobenzene is, however, less reactive that the p- nitrobromobenzene since the NO₂ group at m-position cannot stabilize the intermediate carbanion by resonance. Thus, option (b), i.e., II > IV >III > I is correct.

(Acetylsalicylic acid) – B (Drug ).

II (DDT) – A (Insecticide),

III (Naphthalene) – C (Moth repellent),

IV ( Carbon – tetrachloride – D (Fire extinguisher).

Although due to + I – effect of the CH₃ groups, (CH₃)₂ CHO^– and (CH₃)₃CO^– are stronger, bases but due to steric hindrance both are weaker nucleophiles than CH₃O^–. Further, due to resonance C₆H₅O^– is the weakest nucleophile Thus, option (1) is correct.

The formation of a mixture of o – and m – toluidine certainly suggests that the triple bond in benzyne is between o-and m-position and hence option (2) is correct.

Benzyl Chloride or α – chlorotoluene is an organic compound , which is a colorless liquid and is a more reactive organic compound. Hence it is widely used chemical building block.

Trihalogenated methane (CHX₃) and a primary amine i.e,

CHX₃ + RNH₂ + 3KOH → RNC + 3KX + 3H₂O

Cl in 2, 4, 6 – trinitrochlorobenzene is activated by three NO₂ groups at o, and p – positions and hence undergoes hydrolysis most readily

The order of reactivity follows the sequence: benzyl halides > alkyl halides > aryl halides. Out of chlorides and bromides, bromides are more reactive.Therefore, the correct order of reactivity is : PhCH₂Br (ii) > MeBr (i) > MeCl (iii) p-MeOC₆H₄Br (iv) i.e. option (4) is correct.

The dipole moment of p – dichlorobenzene is zero since the two equal dipoles oppose each other. The two dipoles are at 60^o apart in o – dichlorobenzene but at 120^o is m – dichlorobenzene, therefore, according to parallelogram law of forces, the dipole moment of o-dichlorobenzene is much higher than that of m – isomer. Toluene due to + I – effect of the CH₃ group has a small but finite dipole moment, therefore, the overall order is p-dichlorobenzene (IV) < toluene (I) < m-dichlorobenzene (II) < o – dichlorobenzene (III). i.e, option (2) it is correct.