1What is the order of relative acidity for phenols, carboxylic acids, alcohols, and water
Carboxylic acids > Phenols > Water/Alcohols
2How can you demonstrate the relative acidity of carboxylic acids against phenols and water?
Test with sodium hydrogencarbonate. Only carboxylic acids are strong enough acids to form colourless $CO_2$ bubbles
3What affects the acidity of carboxylic acids?
The presence of other substitute groups
4How does the acidity of ethanoic acid compare to that of trichloroethanoic acid
Ethanoic acid is much weaker. The presence of the chlorine groups provides an additional stability to the carboxylic ion, allowing a greater degree of dissociation
5What is the organic ion formed from the disociation of a carboxylic acid?
The carboxylate ion
6Describe the stability of the carboxylate ion
Carboxyalate ions are more stable than expected as the negative charge is distrubuted across both oxygens, leading to a resonance energy
7How may carboxylic acids be formed?
The oxidation of primary alcohols and aldehydes, and the hydrolysis of a nitrile
8What are the conditions and reagents neccesary for the formation of a carboxylic from an aldehyde or an alcohol?
Acidified potassium dichromate under heated reflux
9What are the conditions and reagents neccesary for the formation of a carboxylic from a nitrile?
Heated under reflux with a dilute acid such as dilute hydrochloric acid
10Give the formula for the hydrolysis of R-CN
$RCN + 2H_2O + H^+ \rightarrow RCOOH + NH_4^+$
11How can alcohols be formed from carboxylic acids?
Reduction using lithium tetrahydridoaluminate
12Can aldehydes be formed directly from the reduction of carboxylic acids?
No, as the reaction cannot be stopped mid-way through
13Give the general equation for the reduction of a carboxylic acid
$RCOOH + 4[H] \rightarrow RCH_2OH + H_2O$
14How can aromatic carboxylic acids be formed?
Oxidation of carbonyl side chains
15What are the conditions and reagents neccesary for the formation of an aromatic carboxylic
Alkaline potassium manganate under heated reflux
16What is formed from the oxidation of R-yl benzene
Regardless of side chain length, sodium benzoate is always formed. This may then be converted in to benzoic acid by adding a stronger acid
17What is the process and general equation for decarboxylation?
Reaction of the carboxylic acid with soda lime (NaOH & CaO)
$RCOOH + 2NaOH \rightarrow R + Na_2CO_3 + H_2O$
18What is an acid chloride?
A compound with the COCl functional group
19How can acid chlorides be formed?
Using $PCl_3, PCl_5, or SOCl_2$
20What is the prefered method for the formation of an acid chloride?
Using thionyl chloride ($SOCl_2$), as all secondary products are gaseous, so fewer purification steps are required
21What other useful products can carboxylic acids be used to make?
Esters, amides, and nitriles
22How can esters be formed from carboxylic acids?
Heating with alcohols in the presence of a protenating (conc ${H_2SO_4}$) catalyst
23What is the problem with the formation of esters directly from carboxylic acids?
The reaction is reversible, and the equilibrium lies towards the side containing the alcohol and the carboxylic acid
24What is an alternative industrial catalyst used for the formation of carboxyic acids from
25What is the preferred method for formation of esters from alcohols?
Reaction of the alcohol with an acid chloride at room temperature
26Why are acid chlorides preferred for the formation of esters?
The reaction is non-reversible, and the only secndary product is the gaseous HCl, reducing the need for purification steps. It is not ideal for classroom use
27What is the hydrolysis of an ester?
The reverse of condensation esterification; the reaction of an ester with water to give an alcohol and a carboxylic acid
28Compare the rates of hydrolysis of acid chlorides and esters
Acid chlorides are very rapidly hydrolysed when compared to esters
29How can amides ($CONH_2$) be formed from carboxylic acids?
Reacting the carboxylic acid with aqueous ammonia to form the ammonium salt ($NH_4^-$). This may then be dehydrated by heating
30How can nitriles (RCN) be formed from an amide ($CONH_2$)?
The dehydration of an amide by heating with phosphorus(V) oxide ($P_4O_{10}$)
31How else may nitriles (RCN) be formed?
The reaction of a halogenalkane with potassium cyanide under heated reflux (nucleophilic sub)
32How may amides be hydrolysed?
Using a dilute acid
33Give the general equation for the hydrolysis of an amide
$CONH_2 + H_2O \xrightarrow{[H^+]} COOH + NH_3$