Problem 27
Which of the following represents the correct decreasing relative reactivity towards an electrophile, \(E^{19}\) (1) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{3}, \mathrm{p}-\mathrm{CH}_{3} \mathrm{C}_{6} \mathrm{H}_{4} \mathrm{CH}_{3}\), \(\mathrm{p}-\mathrm{CH}_{3} \mathrm{C}_{6} \mathrm{H}_{4} \mathrm{NO}_{2}, \mathrm{p}-\mathrm{NO}_{2} \mathrm{C}_{6} \mathrm{H}_{4} \mathrm{NO}_{2}\) (2) \(\mathrm{p}-\mathrm{CII}_{3} \mathrm{C}_{6} \mathrm{I}_{4} \mathrm{CH}_{3}, \mathrm{p}-\mathrm{CII}_{3} \mathrm{C}_{6} \mathrm{II}_{4} \mathrm{NO}_{2}\) \(\mathrm{p}-\mathrm{NO}_{2} \mathrm{C}_{6} \mathrm{II}_{4} \mathrm{NO}_{2}, \mathrm{C}_{6} \mathrm{I}_{5} \mathrm{CII}_{3}\) (3) \(\mathrm{p}-\mathrm{CII}_{3} \mathrm{C}_{6} \mathrm{H}_{4} \mathrm{NO}_{2}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CII}_{3}\), \(\mathrm{p}-\mathrm{CII}_{3} \mathrm{C}_{6} \mathrm{I} \mathrm{I}_{4} \mathrm{CH}_{3}, \mathrm{p}-\mathrm{NO}_{2} \mathrm{C}_{6} \mathrm{I}_{4} \mathrm{NO}_{2}\) (4) \(\mathrm{p}-\mathrm{CII}_{3} \mathrm{C}_{6} \mathrm{II}_{4} \mathrm{CH}_{3}, \mathrm{C}_{6} \mathrm{II}_{5} \mathrm{C} \mathrm{II}_{3}\), \(\mathrm{p}-\mathrm{CII}_{3} \mathrm{C}_{6} \mathrm{H}_{4} \mathrm{NO}_{2}, \mathrm{p}-\mathrm{NO}_{2} \mathrm{C}_{6} \mathrm{I}_{4} \mathrm{NO}_{2}\)
Problem 35
Which separates by sulphonation? (1) 0-xylene (2) m-xylene (3) p-xylene (4) All
Problem 40
Why does 1,3 -cyclohexadiene undergo dehydrogenation readily? (1) It can be easily reduced (2) It has no resonance energy (3) It gains considerable stability by becoming benzene (4) It cannot undergo dehydrogenation
Problem 48
The sulphonation of chlorobenzene gives exclusively (1) an o-product (2) an m-produet (3) a p-product (4) an o-, \(\mathrm{p}\) -disubstituted product
Problem 49
When an aromatic compound undergoes ozonolysis followed by treatment with \(\mathrm{I}_{2} \mathrm{O} / \mathrm{Zn}\), it produces glyoxal, monomethyl glyoxal and dimethyl glyoxal. It could be (1) benzene (2) toluene (3) 0 -xylene (4) m-xylene
Problem 50
Which of the following is the most reactive towards clectrophilic nitration? (1) Benzene (2) Toluene (3) Benzoic acid (4) Nitrobenzene
Problem 51
Which form of xylene is most casily sulphonated? (1) ortho- (2) meta- (3) para- (4) All are sulphonated at the samc rate
Problem 52
Which form of xylene has only one monobromo derivative? (1) ortho- (2) para- (3) meta- (4) None of these
Problem 57
Toluene can be converted into benzaldehyde by oxidation with (1) \(\mathrm{KMnO}_{4}\) /alkali (2) \(\mathrm{CrO}_{2} \mathrm{Cl}_{2}\) (3) \(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} / \mathrm{H}_{2} \mathrm{SO}_{4}\) (4) \(\mathrm{O}_{2} / \mathrm{V}_{2} \mathrm{O}_{5}\)
Problem 59
The stability of the free radicals allyl, benzyl, \(3^{\circ}, 2^{\circ}\), \(1^{\circ}\) and \(\mathrm{CH}_{3}\) is of the order (1) allyl=benzyl \(>3^{\circ}>2^{\circ}>1^{\circ}>\mathrm{CH}_{3}\) (2) allyl \(>\) benzyl \(>3^{\circ}>2^{\circ}>1^{\circ}>\mathrm{CH}_{3}\) (3) \(3^{\circ}>2^{\circ}>1^{\circ}>\mathrm{CH}_{3}>\) allyl \(>\) benzyl (4) \(3^{\circ}>2^{\circ}>1^{\circ}>\mathrm{CH}_{3}>\) allyl=benzyl
