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Butanoic acid (b.p 163.5 degree C) has higher boiling point than ethylacetate (C

ID: 1021895 • Letter: B

Question

Butanoic acid (b.p 163.5 degree C) has higher boiling point than ethylacetate (CH_3(C=O)OCH_2CH_3, b.p. 77 degree C) although they have the same molecular weight. Briefly provide your reasoning. Arrange each group of compounds in order of increasing acidity. Ethane Ethanol Acetic acid more acidic less acidic Benzoic acid o-Fluorobenzoic acid m-Fluorobenzoic acid more acidic less acidic Acetic acid Chloroacetic acid Fluoroacetic acid more acidic less acidic What is the most acidic molecule characterized by the formula C_3H_xO_2(x=any number between 1 - 9)? Draw the structure of the compound.

Explanation / Answer

In the case of butanoic acid

CH3-CH2-CH2-COOH, there is a strong hydrogen bonding because of the presence of bond between Oxygen which is highly electronegative and Hydrogen

In th case of ethyl acetate there is no hydrogen bonding since the compound structure will be CH3-CO-CH2-CH3

Hence the lack of hydrogen bonding in ethyl acetate will result in lesser boiling point

b)

The correct order will be

CH3COOH > C2H5OH > C2H6

Reason: Acetic acid after loosing H+ will have equivalent resonance structures by sharing the charge on the Oxygen atom. In the case of C2H5OH, the negative charge will be present on highly electronegative element and in the case of C2H6,.the compound form will be CH3-CH2-, CH3 will have +H and +I effect will push more electrons to CH2- group, hence the compound will be unstable

ii) The correct answer is O-flouro benzoic acid > m-flouro benzoic acid > benzoic acid

iii) Correct order flouro acetic acid > chloro acetic acid > acetic acid

Since F and Cl are -I groups, hence it will help in withdrawing more electrons and will help in leaving H+ easier as compared to normal acetic acid

The flourine is highly electronegative element, hence the structure will be more stable because flourine withdrawing capacity is more than Chlorine