Compounds I and II can be distinguished by using reagent
(3) HCI/ZnCI2 (anhydrous)
(4) Cu2CI2 + NH4OH
Compare rate of dehydration of (i), (ii) and (iii) by conc. H2SO4.
(a) (i)>(iii)>(ii) (b) (i)>(ii)>(iii)
(c) (ii)>(i)>(iii) (d) (ii)>(iii)>(i)
Concept Questions :-
In each of the following groups, which is the strongest (best) nucleophile ?
(I)(1)H3C-O- (2) (3)H3C-S- in CH3OH
(II)(1)OH- (2) H2O (3) in DMF
(III) (1) (2) (3) CH3O- in DMSO
(a) I,3; II,3; III,2 (b) I,2; II,1; III,3
(c) I,1; II,2; III,1 (d) I,3; II,1; III,3
Which of the following statements is true?
(a) CH3CH2S- is both a stronger base and more nucleophilic than CH3CH2O-
(b) CH3CH2S- is a stronger base but is less nucleophilic than CH3CH2O-
(c) CH3CH2S- is a weaker base but is more nucleophilic than CH3CH2O-
(d) CH3CH2S- is both a weaker base and less nucleophilic than CH3CH2O-
What sequence of reagents is required to accomplish the following transformation?
1. (1) NBS, ROOR (2) CH3CH2O- (3)2HBr (4) NH-2 (5) disiamylborane (6) H2O2,OH-
2. (1) Cl2hv (2) OH-, heat; (3) 2HCl (4) OH-,heat (5) HgSO4,H2SO4
3. (1) NBs,ROOR; OH-,DMSO
4. (1) Br2,hv (2) t-butoxide (3) BH3,THF (4) H2O2,OH-
Consider the following alcohols
The order of decreasing reactivities of these alcohols towards substitution with HBr is :
(a) III > I > IV > II
(b) III > I > II > Ⅳ
(c) I > III > IV > II
(d) I > III > II > IV