1.carbonylys acids and esters

Question 1

what is a carbonyl compound?

Answer 1

a keytone or a aldehyde

Question 2

what kind of reaction does a carbonyl bond tend to undergo? (C=O)

Answer 2

neucleophillic addition

Question 3

what is the neucleophile in the neucleophilic addiditon of a carbonly bond?

Answer 3

H^-

from NaBH₄

Question 4

mechanism for the neucleophillic addition of a carbonyl compound?

Answer 4

Question 5

what oxidising agent fo you use?

Answer 5

Cr₂O₇^2-/H⁺

acidified dicramate ions

K₂Cr₂O₇/H⁺

Question 6

form a keytone?

Answer 6

secondary alcohol

reflux

acidified dicromate

Question 7

form an aldehyde?

Answer 7

primary alcohol

acidified dicromate in 1:1 ratio

add [0] to alcohol drop wise

distil as it forms

Question 8

Equation for the reduction of ethanal to ethanol

Answer 8

CH₃CHO + 2[H] —> CH₃CH₂OH

Question 9

WHat is tollens reagent?

Answer 9

ammonical silver nitrate solution

A silver mirror is formed upon the addition of an aldehyde

Question 10

possitive test for tollens?

Answer 10

SIlver mirror in aldehyde presence

Question 11

how to make tollens reagent?

Answer 11

1. Silver nitrate + NaOH (brown precip AgOH formed)
2. Add enough NH₃ to remove the precipitate as it becomes a complex ion.

Question 12

Tollens reagent reaction?

Answer 12

Aldehyde + [O] —> Carboxilic acid

Question 13

What does 2,4-DNPH test for?

Answer 13

aldehydes and keytones

Question 14

What is 2,4-DNPH solution

Answer 14

its an orange solution that when mixed with methanol and sulfuric acid becomes the oxidising agent

Question 15

2,4-DNPH stands for?

Answer 15

2,4-dinitrophenylhydrazine

Question 16

positive test for 2,4-DNPH?

Answer 16

an orange or yellow precipitate called 2,4-DNPH derivitive is formed.

Question 17

What can the 2,4-DNPH derivitie be used for?

Answer 17

• identifying the carbonyl compound
• First Filter and recrystalize it to purify it
• find the melting point of the crystals
• compare this to a database to identify the compound.

Question 18

2,4-DNPH reaction?

Answer 18

The H₂ from the hydrazine section of 2,4-DNPH is lost , as well as the O on the carbonly they formm water.

The other two form a hydrozone.

Question 19

What kinds of carboxilic acid are water soluble and why?

Answer 19

• Chains between 1-4 carbons
• the polar end of the acid makes up a large proportion, this can hydrogen bond witht he water

Question 20

Esterification reaction

Answer 20

Alcohol + Carboxylic acid —> ester +water reflux, conc sulfuric acid catalyst,warm.

Question 21

Making an ester from an anhydride and its benifits?

Answer 21

Anhydride + methanol–> ester + carboxillic acid

heat

Better yield then other method

Question 22

Define Hydrolysis

Answer 22

Is a draction with water or hyroxide ions that breaks a chemical compound into two compounds

Question 23

Acid Hydrolysis of an ester

Answer 23

Ester heated under refulx with dilute sulfuric acid (or dilute HCL) with water

Forms alcohol and a carboxillic acid

Question 24

Alkali Hydrolisis of an ester?

Answer 24

AQUEOUS Sodium/potassium hydroxide is refulxed with the ester

forms metal salt of carboxillic acid and an alcohol.

Question 25

Uses of esters?

Answer 25

• Perfumes
• Flavourings

Question 26

name of a metal carboxillic acid salt?

Answer 26

metal <chain>anoate known as carboxylates</chain>

eg sodium methanoate

Question 27

Why do carboxillic acids dissociate more then alcohols?

Answer 27

The -COO^- is more stable then -CO^-

this is due to the charge being distributed across more atoms

Question 28

Making biodiesel?

Answer 28

triglyceride + 3 alcohol (short chain) —> glyserol + 3 ester

NaOH catlyst

Question 29

Elimination of H₂O from alcohol.

Answer 29