Chemistry

This is a multiple choice answer as classified in NCERT Exemplar

The Correct Answer is Option (iii).

The presence of electron releasing groups increases the reactivity of aryl halides; the fewer the electron releasing groups, the slower the rate of nucleophilic substitution. As a result, an increase in methyl groups decreases reactivity. The sequence of reactivity is (a) > (b) >   (c). The right answer is (iii).

This is a multiple choice answer as classified in NCERT Exemplar

The Correct Answer is option (iv).

( - NO₂) is an electron-withdrawing group that induces nucleophilic substitution when it is in the ortho and para positions. When this identical electron-drawing group is in the meta position, its impact is much reduced. The reactivity of aryl halides rises as the number of electron-withdrawing groups increases. As a result, the greater the number of electron-drawing groups, the greater the rate of nucleophilic substitution.

This is a multiple choice answer as classified in NCERT Exemplar

The Correct Answer is Option (iv).

Because the -CH₃  group is an electron releasing group, it reduces the reactivity of aryl halides in the ortho and para locations. As a result, aryl halides without electron releasing groups are more reactive. As a result, the order of reactivity is (a) > (c) > (d) (b). The right answer is (iv).

This is a multiple choice answer as classified in NCERT Exemplar

The Correct Answer is Option (iii).

Due to the resonance stabilisation of the benzene ring, the reactivity of aryl halides to nucleophilic substitution is exceedingly low. Because of resonance, the -Cl bond gains a partial double bond. The presence of an electron withdrawing -NO₂ group at ortho or para positions on the ring enhances the reactivity of aryl halides. The presence of -NO₂ near the C-Cl makes the molecule more reactive. The order of reactivity should be (b) > (c) >   (a). The right option is (iii).

This is a multiple choice answer as classified in NCERT Exemplar

The Correct Answer is Option (ii).

Chiral molecules are made up of one carbon atom surrounded by four different species. Because of the presence of two or more identical groups, such as hydrogens, all straight chain molecules cannot be chiral. Even carbons with double or triple bonds to a group are not considered chiral. Through covalent connections, an asymmetric carbon must be surrounded by four distinct species. As a result, atoms b and c are asymmetric. The correct answer is option (ii).

This is a multiple choice answer as classified in NCERT Exemplar

The Correct Answer is Option (i).

The structure of 2-Bromobutane is depicted in the diagram below. Because all of the groups connected to the central carbon atom differ, the mirror image of the molecule cannot be superimposed on the original molecule.

The structure of 1-Bromobutane is shown in the diagram below. Because there are just three groups that vary from one another, the molecule is not chiral in nature.

The structure of 2-Bromopropan-2-ol, shown below, has two identical species and hence cannot be chiral.

This is a multiple choice answer as classified in NCERT Exemplar

The Correct Answer is Option (iii).

Because it possesses unpaired electrons, the ammonia molecule is a nucleophile in nature. By nucleophilic substitution, this nucleophile attacks the chloromethane molecule and forms methyl amine or methanamine. The carbon atom in the molecule is partially positive due to the electronegativity of the linked halide, which is partially negative. The positive ion is attacked by the electron-rich nucleophile, causing the halide ion to be detached from the molecule. The proper response is (iii).