(r)-2-butanol reacts with potassium dichromate (k2cro4) in aqueous sulfuric acid to give a (c4h8o). treatment of a with sodium b
orohydride in ethanol gives b, which as the same boiling point and refractive index as (r)-2-butanol. draw the structure of
b.
b.
1 answer:
Potassium dichromate reacts with sulfuric acid to form chromic acid, H₂CrO₄ which is a very strong oxidizing agent. The secondary alcohol, (<em>R</em>)-2-butanol will be oxidized in the presence of chromic acid, but it can only be as oxidized as far as the ketone, which is the product shown, 2-butanone.
Sodium borohydride is a reducing agent that will reduce a ketone or aldehyde to an alcohol. When sodium borohydride reacts with 2-butanone, it reduces it to 2-butanol. However, the alcohol is no longer chiral as it was in the beginning since the sodium borohydride can add a hydride to either face of the carbonyl, which results in a racemic mixture of alcohols. This explains why the product has the same refractive index and boiling point as (<em /><em>R</em>)-2-butanol, however, the product formed would no longer be optically active.
Sodium borohydride is a reducing agent that will reduce a ketone or aldehyde to an alcohol. When sodium borohydride reacts with 2-butanone, it reduces it to 2-butanol. However, the alcohol is no longer chiral as it was in the beginning since the sodium borohydride can add a hydride to either face of the carbonyl, which results in a racemic mixture of alcohols. This explains why the product has the same refractive index and boiling point as (<em /><em>R</em>)-2-butanol, however, the product formed would no longer be optically active.
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Heat energy released : 167.2 kJ
<h3>Further explanation</h3>Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
m = 2000 g
c = 4.18 J/ g ° C
∆t = 20 ° C