Chemistry

46. This is a Multiple Choice Questions as classified in NCERT Exemplar

Carbocation is correct since H⁺ attacks on propene and the delocalization of electrons can take place in two possible ways which can be shown as-

This is a Multiple Choice Questions as classified in NCERT Exemplar

45. Option (iv) is found to be the correct one since the stabilisation of carboxylate ion depends upon the dispersal of the negative charge. And the dispersal depends upon two factors, i.e., +R effect of the carboxylate ion and Inductive effect of the halogens. In all the above structures, +R effect is common, but halogen atoms are uncommon. Therefore, dispersal of negative charge depends upon the halogen atoms. Fluorine is most electronegative, in structure (iv) two F atoms are present and hence more dispersal of negative charge is there.

This is a Multiple Choice Questions as classified in NCERT Exemplar

44. Option (i)

is found to be the correct one since the order of electronegativity of the attached group is found to be: 

Cl > Br > C > Mg. 

Greater the electronegativity of the group attached to the C  greater will be the positive charge. Therefore, in case (i) asterisk C will have the greatest positive charge.

71.  (i) - (c); (ii)- (d); (iii)- (b); (iv)- (e)

70.  (i) - (b); (ii)- (d); (iii)- (a); (iv)- (e); (v)- (c)

69.  (i) - (d); (ii)- (a); (iii)- (b); (iv)- (e); (v)- (f)

68.  (i) - (c); (ii)- (a); (iii)- (e); (iv)- (b)