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General Chem help? 1.) With which of the following carbonyl compounds does ethyl

ID: 895664 • Letter: G

Question

General Chem help?

1.) With which of the following carbonyl compounds does ethylmagnesium bromide react to form an alcohol which can be resolved into a pair of enantiomers?

A.acetone
B.butanone
C.acetaldehyde (ethanal)
D. propanal
E.cyclopentanone

2).What is the product of oxidation of 2-pentanone? ( I thought no reaction)

A.pentane
B.2-pentanol
C.pentanoic acid
D.1-pentanal
E.no reaction

3.)When aldehydes are mixed in a dilute acid, they undergo:

A. oxidation, forming a secondary alcohol.
B. aldol condensation, forming a hydroxylated aldehyde.
C. nucleophilic substitution, forming an alkyl halide.
D. keto-enol tautomerism, forming a carboxylic acid.

4.)Both aldehydes and ketones can be reduced to alcohols. T or F

5.) The carbonyl group is _________ with the carbon being slightly _________ and the oxygen being slightly ___________.

A.polarized, negative, positive
B.polarized, positive, negative
C.neither (A) nor (B)
D.both (A) and (B)

6.)Which of the following compounds undergo reduction with H2/Pt?

A.CH3(CH2)3COCH3
B.CH3(CH2)3CHO
C.CH3(CH2)3CH2OH
D.A and B
E.all of the above

7.)An aldehyde group always occurs at the end of a carbon chain. T or F

8.)The molecule (CH3)2C(OH)CN is an example of a (an):

A.semicarbazone
B.hydrazone
C.cyanohydrin
D.hemiacetal
E.none of these

Explanation / Answer

1.) Of the following carbonyl compounds the one with which ethylmagnesium bromide react to form an alcohol and which can be resolved into a pair of enantiomers is,

C.acetaldehyde (ethanal)

Only acetaldehyde would result in an alcohol which has a carbon with all four groups different, which is neccesary for a molecule to be chiral.

  

2).The product of oxidation of 2-pentanone would be,

E. no reaction

3.) When aldehydes are mixed in a dilute acid, they undergo:

B. aldol condensation, forming a hydroxylated aldehyde.

4.) Both aldehydes and ketones can be reduced to alcohols. : T

Aldehydes give primary alcohol whereas ketones yield a secondary alcohol on reduction.

5.) The carbonyl group is _________ with the carbon being slightly _________ and the oxygen being slightly ___________.

B.polarized, positive, negative

6.) The following compounds undergo reduction with H2/Pt,

D. A and B

H2/Pt will reduce both the aldehyde and the ketone to corresspnding alcohol.

7.) An aldehyde group always occurs at the end of a carbon chain. : T

Aldehyde is -CHO functionality which requires an H to be attached to the C=O.

8.) The molecule (CH3)2C(OH)CN is an example of a (an):

C.cyanohydrin