R/Cs for all organic cpds

Question 1

What functional groups react with Na(s)?

Answer 1

Alcohol and phenol

Question 2

What functional groups will react in the presence of water?

Answer 2

Acyl chloride (only requires H2O for hydrolysis)

Question 3

What reaction occurs with alumina and heat?

Answer 3

alcohol undergoes elimination to form alkene. (apply Saytzeff Rule)

Question 4

What are the R/Cs for Iodoform test? State the type of reaction.

Answer 4

Aqueous Iodine in NaOH (aq), wam

Question 5

In which reactions are the formation of a bromide ion involved at some stage?

Answer 5

1. E.A. of alkenes and Br2 (l) or Br2 (aq)
2. N.S. Williamson synthesis of CH3CHBrCH3 + CH3O-Na+
3. N.S. of an R-Br compound

Question 6

What is the difference between the resonance effect and inductive effect of the benzene ring?

Answer 6

Resonance effect involves the pi bond only; involves overlap of p orbital on substituent with p orbital on the carbon atom of the benzene ring. e.g. -CHO group

Inductive effect involves sigma bonds only; due to electronegativity differences between the atoms. e.g. electron-donating -CH3 group

Question 7

What is the ratio for balancing the equation of Iodoform test for carbonyl compounds?

Question 8

Can esters undergo reduction with LiAlH4 in dry ether?

Answer 8

Yes

Question 9

What are the positive observations for mild oxidation of alkenes in ALKALINE medium?

Answer 9

1. Purple KMnO4 decolourises
2. Brown ppt of MnO2 is formed.

Question 10

What are the positive observations for mild oxidation of alkenes in ACIDIC medium? (i.e. cold KMnO4(aq) in dilute sulfuric acid)

Answer 10

1. Purple KMnO4 declourises.

Note: the brown ppt of MnO2 is only formed in alkaline medium with cold KMnO4. In acidic medium, MnO4- will be fully reduced to Mn2+, which is colourless.