COLOUR BY DESIGN

What is the MOLECULAR formula of benzene? :3

C6H6

What is the empirical formula of benzene?

CH

Why may the formulae of benzene ‘C6H6’ confused scientist who discovered it?

v.little H compared to C

If Kekule’s benzene structure was correct, what observation would happen when bromine water was added to a sample of benzene?

Turn orange to colourless

What actually happens when bromine water is added to benzene? (observation wise)

Remains orange

Why would kekule’s benzene structure be an irregular hexagon rather than a regular one?

Because double bonds are shorter than single bonds

If kekule’s benzene structure was correct, what would the shape be?

An irregular benzene

What is the shape of actual benzene?

A regular hexagon

What is the bond angle within benzene?

120

If kekule’s benzene structure were to go through electrophilic addition reaction with a halogen, how many isomers would there be?

2

What are pi bonds? (long ass answer)

Sideways overlap of 2 parallel p orbitals above and below the internuclear axis

Describe the formation of the ring within a benzene. (long ass answer/ exam answer)

There are 6 delocalised e-, one from each C, in an extended pi system above and below the ring of C’s

What is aromatic?

With benzene ring

What is aliphatic?

Without benzene ring

Name this compound.

Chlorobenzene

Name this compound.

2-chlorobutane

Name this compound.

Methylbenzene

Name this compound.

Cyclohexanol

Name this compound.

Benzoic acid

Name this compound

Phenol

Name this compound.

Ethanoic acid

Name this compound.

Methylbenzoate

Name this compound.

Methylethanoate

Name this compound.

Phenylamine

Name ts compound

1-aminohexane

Name ts compound.

2-phenylpropanal

Name ts compound.

Propanal

Name ts compound.

Benzaldehyde

When drawing fused benzene rings, do you draw with rings or c=c?

c=c

What reaction can benzene do?

Electrophilic substitution

What would happen if benzene ‘theoretically’ went though an addition reaction?

Delocalised pi system is lost, stability decreases

Why do benzene not go do addition reactions?

Delocalised pi system is lost, stability decreases

Why are substitution reactions good for benzene?

Delocalised pi system is retained, maintaining its stability

What are the reagents / catalysts / conditions in bromination?

Br2 / FeBr3

What are the reagents / catalysts / conditions in chlorination?

Cl2 / AlCl3 / anhydrous

What are the reagents / catalysts / conditions in sulphonation?

c.H2SO4 / reflux

What are the reagents / catalysts / conditions in nitration?

c.HNO3 / c.H2SO4 / <55 degrees

What are the reagents / catalysts / conditions in Friedel Crafts reactions?

R+ / AlCl3 / anhydrous / reflux

What are the products in bromination?

Bromobenzene AND hydrogen bromide (HBr)

What are the products in chlorination?

Chlorobenzene AND hydrogen chloride (HCl)

What are the products in sulphonation?

Benzene sulphonic acid / H2O

What are the products in nitration?

Nitrobenzene / H2O

What would happen if temperature exceeds 55 degrees in nitration?

If the reaction gets above 55, di or tri substitution can occur, which makes v.reactive / explosive products

What is the electrophile in bromination?

Br +

What is the electrophile in chlorination?

Cl +

What is the electrophile in sulphonation?

SO3

What is benzene sulphonic acid often reacted with? and why?

NaOH, to make a salt and can form ion-dipole forces with H2O / now soluble

What is the name of the salt produced by benzene sulphonic acid + NaOH?

Sodium benzene sulphonate

Where does the electrophile: SO3 come from in sulphonation?

H2SO4

What is the electrophile in nitration?

NO2+

What is the balanced equation that makes the electrophile in nitration?

HNO3 + 2H2SO4 → NO2+ + 2HSO4- + H3O+

What is the balanced equation that makes NO2+ in nitration?

HNO3 + 2H2SO4 → NO2+ + 2HSO4- + H3O+

What is the balanced equation that makes NO2+?

HNO3 + 2H2SO4 → NO2+ + 2HSO4- + H3O+

What does the R+ mean in Friedel Crafts reaction?

A Carbon / carbon compound

What are the 2 variations of Friedel Crafts reactions?

Alkylation / Acylation

What is Friedel Crafts alkylation?

Adding an alkyl group

What is Friedel Crafts acylation?

Adding an acyl group

What compound do you use to make the electrophile (R+) for Friedel Crafts alkylation?

A haloalkane

What are the reagents / catalysis / conditions for this reaction?

AlCl3 / anhydrous / reflux

What compound do you use to make the electrophile (R+) for Friedel Crafts acylation?

Acyl chloride OR acid anhydride

What is the NAME of an acyl chloride with 4 carbons?

Butanoyl chloride

What is the written structure of butanoyl chloride?

CH3CH2CH2COCl

What is the written structure of propanoic anhydride??

(CH3CH2CO)O

What are all (4.5) reactions of alcohol (as a side chain of benzene but dont worry about this detail 🙂)?

Oxidation / esterification / dehydration & elimination / nucleophilic substitution

(QQS) What is a diazonium ion? (long ass answer ._.)

An aromatic compound with a N(triple bond)N attached where the N with 4 bonds is positive

(QQS) What is the first stage of forming azo compounds?

Diazotisation

(QQS) What is the mechanism of the coupling reaction?

Electrophilic substitution

(QQS) How do u find what reactants were used to make an azo dye?

Split up the azo dye on one side of the N=N

(QQS) What are the conditions for diazotisation? and why?

<5C, to prevent decomposition as N+(triple bond)N is very unstable

What are the conditions for diazotisation?

<5C

Why does the conditions for diazotisation need to be <5C?

Prevent decomposition as N+(triple bond)N is very unstable

What is the reaction that needs to be under 5C?

Diazotisation

What is the reaction that needs to be <5C

Diazotisation

(QQS) What is a typical coupling reagent?

An aromatic compound with a phenol or an amine group

(QQS) What are the 2 reactants required to form nitrous acid?

Sodium nitrite and an acid (HCl)

(QQS) What 3 reactants are needed to form a diazonium ion?

Phenylamine / nitrous acid / an acid (HCl)

(QQS) What conditions are needed for the coupling reaction?

Alkaline

(QQS) What is the chromophore?

The part of the molecule which gives it its colour

(QQS) What is an azo group?

N=N

(QQS) What is the second stage of making an azo dye?

The coupling reaction

Where would as azo group need to be, in order to be stable?

In between 2 benzene rings

In terms of pi bonds, what happens to the azo group when it is in between benzene rings?

The azo group becomes part of the delocalised pi system which increases stability

Why are azo groups (N=N) between 2 benzene rings?

To be stable

Each dye is made from a ____________ and a _____________. (fill in blanks)

Diazonium ion / coupling reagent

WHEN must the diazotisation reaction need to take place?

Just before the coupling reaction

What is the name of NaNO2?

Sodium nitrite

What is the systematic name of NaNO2?

Sodium nitrate (III)

Write the balanced equation to make HNO2

NaNO2 + HCl → HNO2 + NaCl

Write the balanced equation to make nitrous acid

NaNO2 + HCl → HNO2 + NaCl

What is the name of HNO2?

Nitrous acid

What does the diazonium ion act as in an electrophilic substitution reaction with a coupling reagent?

An electrophile

What is the name of the reaction that occurs between a diazonium ion and a coupling reagent?

Electrophilic substitution

During an electrophilic substitution reaction between a diazonium ion and a coupling reagent, which atom/molecule is replaced? and from which reactant?

H on coupling reagent is replaced by the diazonium ion

If phenol or phenylamine is the coupling reagent, at what (carbon) position does the substitution take place at?

4th carbon

What is the electrophile in a coupling reaction?

The diazonium ion

What are the conditions for the coupling reaction?

Alkaline

WHAT IS THE EQUATION TO CALCULATE FREQUENCY? ∆

∆E=hv