Suggest a reagent for the following conversion.

1

(a)

CrO₃, pyridine and HCl (pyridinium chloro chromate)

Anhydrous CaCl₂ is not recommended as a drying agent for alcohols and amines.

1

(a)

Alcohols and amines combine with anhyd.CaCl₂ to from complexes.For example,with C₂H₅OH,it gives a complex of molecular formula.CaCl₂.3C₂H₂OH.

What is the order of reactivity of HCl, HBr and Hl with alcohols?

1

(a)

Reactivity decreases as the strength of the H--X bond increases,i.e,Hl  >  HBr  >  HCl

The relative ease of dehydration of alcohols is : tertiary > secondary > primary

1

(a)

The dehydration of alcohols occurs through carbocation intermediates.Since the stability of carbocations decreases in the order 3⁰ >  2⁰  >  1⁰. Therefore, dehydration of alcohols follows the same order,i.e., tertiary > secondary > primary.

Name one reagent which is used for the distinction of primary,secondary and tertiary alcohols

1

(a)

Lucas reagent (anhyd.ZnCl₂+conc.HCl)