chemistry error log

Why does 4-nitrophenol have a higher boiling point than 2-nitrophenol?

Compare the bromination of benzene vs. phenol (conditions and reasoning).

• both undergo electrophilic attack

• bromination of phenol is tribromination and bromination of benzene monobromination

• bromination of benzene requires a halogen carrier such as AlBr3 but phenol does not

How does the O−H absorption differ between ethanoic acid and ethanol in an IR spectrum?

ethanoic acid - very broad peak at 2500-3300

ethanol - broad smooth 3230-3550

key distinction is that ethanoic acid has a peak at 1700 due to presence of c=o

How does the OH bond in a carboxylic acid differ from the OH bond in an alcohol in terms of infrared spectroscopy

The OH bond in a carboxylic acid shows a distinct, extremely broad absorption in IR spectroscopy, generally occurring between

2500--3300cm-1

(often overlapping with C-H stretches), whereas an alcohol's OH bond appears as a strong, broad peak at a higher wavenumber, typically

3200-3600

What are the two-stage observations when adding butylamine dropwise, then in excess, to aqueous copper(II) sulfate?

• at first a light blue precipitate is formed

• when excess the precipitate redissolves to form a deep blue solution

Write the equation for the reaction of [Cu(H2​O)6​]2+ with dropwise butylamine (RNH2​). What is the role of the amine here?

[Cu(H20)6}2+ + 2CH3CH2CH2CH2NH2 —> [Cu(H20)4(OH)2 + 2CH3CH2CH2CH2NH3+

• amine acts as a base (accepts proton from water ligand)

Write the equation for the excess addition of butylamine (RNH2​) to the copper(II) hydroxide precipitate. What is the role of the amine here?

[Cu(H20)6]2+ + 4CH3CH2CH2CH2NH2 —→ [Cu(CH3CH2CH2CH2NH2)4(H20)2] 2+ + 2OH- + 2H20

• the amine acts as a ligand

explain why different alkanes in crude oil can be separated by fractional distillation?

Different alkanes have different boiling points based on their carbon chain length and molar mass

Why does the reactivity of primary halogenoalkanes increase from chloro- to iodoalkanes? (3 Marks)

• down the group the halogen atom gets larger

• distance between 2 nuclei increases so the C-X bond length increases

• the C-X bond becomes weaker and requires less energy to overcome

"Compare the rates of hydrolysis of 1-chlorobutane and 2-chloro-2-methylpropane."

• 1-chlorobutane is primary; 2-chloro-2-methylpropane is tertiary.

• Tertiary halogenoalkanes react via SN​1, while primary react via SN​2.

• The SN​1 mechanism is faster because it involves the formation of a stable tertiary carbocation.

• Inductive Effect: Mention that the three alkyl groups "push" electron density toward the positive carbon, stabilizing it (the inductive effect).

difference in drawing out the mechanism for a primary and tertiary halogenoalkane?

SN1 VS SN2

sn2 - contains a transition state

sn1 - draw two steps (halogen leaving - carbocation intermediate)

How does the classification (type) of a halogenoalkane affect its rate of reaction?

Tertiary > Secondary > Primary

• Tertiary halogenoalkanes react via the SN​1 mechanism.

• Stability: This mechanism involves a carbocation intermediate.

• Inductive Effect: Tertiary carbocations are the most stable because they have three alkyl groups that donate electron density (positive inductive effect) to reduce the charge density on the carbon atom.

Describe the stages by which a catalytic converter converts polluting gases in a car exhaust system? (3 marks)

• adsorption of gases to catalytic surface

• weakening of bonds on catalytic surface

• desorption of products from catalytic surface

What are the conditions and reactants required for the conversion of benzene to nitrobenzene?

conc. HNO3 and H2SO4 heated under reflux with 50 degrees

COnditions and reactant required for the conversion of nitrobenzene to a phenyl amine

conc HCl and Tin - heated under reflux

What two reactions can be done to nitriles?

hydrolysed and reduction

Conditions and reactant required for the hydrolysis of a nitrile

acidic hydrolysis : dilute HCl heated under reflux to form carboxylic acid and ammonium salt

alkaline hydrolysis : NaOH and h20 heated under reflux to form sodium carboxylate salt and ammonia gas

Write a full redox equation from the half equations for following the two changes combined

MnO4- —> Mn2+

C2O4 2- —> CO2

2MnO4_ + 16H+ + 5C204 2- —> 2Mn2+ + 8H20 + 10CO2