IBChemistryHLTopic QuestionsWhat are the Mechanisms of Chemical Change?Electron Pair Sharing Reactions

Syllabus Edition

First teaching 2023

First exams 2025

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Electron Pair Sharing Reactions (HL IB Chemistry)

Topic Questions

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11 mark

Which of these compounds would act as a nucleophile?

  • C2H6

  • H+

  • OH-

  • Al

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21 mark

Ethene reacts with steam in the presence of sulfuric acid.

C2H4  +  H2O →  CH3CH2OH

What type of reaction is this?

 

  • acid / base

  • addition

  • hydrolysis

  • substitution

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31 mark

Which reaction is an example of nucleophilic substitution?

  • C6H6 + Br2 → C6H5Br+ HBr

  • CH2=CH2 + HBr → CH3CH2Br

  • C3H7Br + H2O → C3H7OH + HBr

  • C2H6 + Br2 → C2H5Br + HBr

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41 mark

Bromomethane, CH3Br, is used as a fumigant to destroy insect pests in grain that is to be stored. It can be made by reacting methanol with hydrogen bromide.

CH3OH  +  HBr  →  CH3Br  + H2O

What type of reaction is this?

  • condensation

  • electrophilic substitution

  • free radical substitution

  • nucleophilic substitution

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51 mark

What reagents and conditions are needed to convert but-2-ene into butane?

  • Concentrated sulfuric acid, steam, 300oC

  • Hydrogen gas, Ni catalyst, 150oC

  • Acidified potassium dichromate, heating under reflux

  • Hydrogen bromide, room temperature

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61 mark

Which species can not act as a ligand?

  • H2O

  • NH4+

  • Cl-

  • OH-

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7
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Which definition of a Lewis acid is correct?

  • Electron pair donor

  • Electron pair acceptor

  • Proton donor

  • Proton acceptor

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8
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Which of the following best describes ammonia, NH3 , in the following equation?

BF3 + NH3 → BF3NH3

  • Lewis acid 

  • Lewis base

  • Coordinate bond

  • Brønsted-Lowry acid 

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91 mark

Which factors affect the rate of nucleophilic substitution in halogenoalkanes?

  1. The nature of the attacking nucleophile
  2. The structure of the halogenoalkane
  3. The identity of the halogen

  •  I and II only

  •  I and III only

  • II and III only

  • I, II and III

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101 mark

Which halogenoalkane reacts fastest with sodium hydroxide?

  • 1-iodobutane

  • 1-chlorobutane

  • 1-bromobutane

  • 1-fluorobutane

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111 mark

Which reagents are needed to convert nitrobenzene to phenylamine in 2 steps?

  Step 1 Step 2
A. tin and concentrated hydrochloric acid sodium hydroxide
B. tin and sodium hydroxide concentrated hydrochloric acid
C. concentrated hydrochloric acid tin and sodium hydroxide
D. sodium hydroxide tin and concentrated hydrochloric acid

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121 mark

Which of the following is true about the structure of benzene?

  1. Benzene has a delocalised structure of π bonds around its ring
  2. Each carbon to carbon bond has a bond order of 1.5
  3. Benzene is susceptible to attack by nucleophiles

  • I and II only

  • I and III only

  • II and III only

  • I, II and III

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13
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4-nitrophenol can be produced from phenol.

20-2-fromiing-4-nitrophenol

What is the name of the mechanism used to make 4-nitrophenol? 

  • Nucleophilic substitution

  • Nucleophilic addition

  • Electrophilic addition

  • Electrophilic substitution

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141 mark

Which reaction(s) can alkenes undergo? 

  1. Addition
  2. Hydration
  3. Reduction

  • I and II only

  • I and III only

  • II and III only

  • I, II and III

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11 mark

Limonene is an oil formed in the peel of citrus fruits.10-2-h-q1-ib-chemistry-mcqs

Which product is formed when an excess of bromine, Br2(l), reacts with limonene at room temperature in the dark?10-2-h-q1-i-ib-chemistry-mcqs

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21 mark

Which compound has an Mr of 84.18 and will react with HBr to give a product with an Mr of 165.09?10-2-h-q3-ib-chemistry-mcqs

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31 mark

Which compound is produced in the reaction between pent-2-ene and steam?

  • (CH3)2CHCH2CH2OH

  • CH3CH(OH)CH2CH2CH2CH3

  • CH3CH2CH2CH2CH2OH

  • CH3CH2CH2CH(OH)CH3

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4
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Copper forms the complex [CuCl4]2-. Which statements are correct for this complex?

  1.   The complex has a tetrahedral shape
  2.   The copper ion has a charge of +2
  3.   The copper ion acts as a Lewis base

  • I and II only

  • I and III only

  • II and III only

  • I, II and III

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5
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Consider the following equation

AgCl + 2NH3→ [Ag(NH3)2]+ + Cl-

Which of the following statements is correct?

  • Silver is acting as a Lewis base

  • AgCl is acting a Lewis base

  • NH3 is acting as a Brønsted-Lowry base

  • Silver ions are acting as a Lewis acid

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6
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Which molecule can react with both sodium borohydride, NaBH4, and warm acidified potassium dichromate(VI)?

  • CH3CHOHCH3

  • CH3C(CH3)2CHO

  • (CH3)3COH

  • CH3C(CH3)2CH2OH

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7
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But-1-ene is reacted first with hydrogen chloride to produce X, which is then reacted with aqueous sodium hydroxide to give Y.

Finally, Y is reacted with excess acidified potassium dichromate solution.

CH subscript 2 CHCH subscript 2 CH subscript 3 rightwards arrow with HCl on top straight X rightwards arrow with NaOH left parenthesis aq right parenthesis on top straight Y rightwards arrow with straight H to the power of plus divided by Cr subscript 2 straight O subscript 7 to the power of 2 minus end exponent left parenthesis aq right parenthesis on top straight Z

What is the major product, Z? 

  • CH3(CH2)2CH2OH

  • CH3COCH2CH3

  • CHOCH2CH2CH3

  • CH3(CH2)3COOH

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8
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Which halogenoalkane will react fastest with a 0.1 mol dm-3 solution of aqueous sodium hydroxide?

  • 2-bromo-2-methylpropane

  • 2-iodo-2-methylpropane

  • 1-bromobutane

  • 1-iodobutane

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9
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Which statement is correct about the major reaction between 1-bromobutane, CH3CH2CH2CH2Br, and dilute sodium hydroxide solution, NaOH (aq)?

  • The rate equation is second order.

  • The hydroxide ion acts as a Brønsted–Lowry acid.

  • The reaction has two distinct steps.

  • Water is a product.

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10
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Which of the following would not be a product of the reaction of pent-1-ene with HCl?

  • CH2ClCHClCH2CH2CH3

  • CHClCH2CH2CH2CH3

  • CH3CH2CHClCH2CH3

  • CH3(CH2)2CHClCH3

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11
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But-1-ene reacts separately with HBr and H2/ Ni to give products X and Z respectively. 

What are the major products of the reactions?

  X Z
A. CH2BrCH2CH2CH3 CH3CH2Cidentical toCH
B. CH3CH2CH2CH2OH CH3CH2CH2CH3
C. CH3CHBrCH2CH3 CH3CH2Cidentical toCH
D. CH3CHBrCH2CH3 CH3CH2CH2CH3

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11 mark

Isomers X and Y both react with HBr.7KgQdxfW_10-2-m-q2-ib-chemistry-mcqs

 A mixture of X and Y is reacted with HBr.

Which three structures represent three different possible products of this reaction?

 A  

(CH3)2CHCBr3

   (CH3)2CBrCHBr2

 CH3CHBrCHBrCH3

B

(CH3)2CHCBr3

(CH3)2CBrCHBr2

CH3CBr2CHBrCH3

C

(CH3)2CBrCBr3

(CH3)2CHCBr3

CH3CBr2CHBrCH3

D

(CH3)2CBrCHBr2

CHBr2CBr(CH3)CH3

CH3CHBrCBr2CH3

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21 mark

In the hydrolysis of bromoethane by aqueous sodium hydroxide, what is the nature of the attacking group and of the leaving group?

 

 

attacking group

leaving group

A

B

C

D

electrophile

electrophile

nucleophile

nucleophile

electrophile

nucleophile

electrophile

nucleophile

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31 mark

In which complexes does iron have an oxidation state of +3? 

  1.   [Fe(H2O)6]3+
  2.   [Fe(H2O)5(CN)]2+
  3.   [Fe(CN)6]3−

  • I and II only

  • I and III only

  • II and III only

  • I, II and III

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41 mark

Ammonia is a stronger ligand than water. Which statement is correct when concentrated aqueous ammonia solution is added to dilute aqueous copper(II) sulfate solution?

  • The d-orbitals in the copper ion split.

  • There is a smaller splitting of the d-orbitals.

  • Ammonia replaces water as a ligand.

  • The colour of the solution fades.

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51 mark

Cobalt forms the complex [Co(NH3)5Cl]2+. Which statements are correct for this complex? 

  1.   The cobalt ion acts as a Lewis acid.
  2.   The cobalt ion has an oxidation state of +2.
  3.   There are 90° bond angles between the cobalt ion and the ligands.

  • I and II only 

  • I and III only

  • II and III only

  • I, II and III

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61 mark

Which of the following statements is not correct?

  • A Brønsted-Lowry base is a proton acceptor

  • Ammonia can act as a Brønsted-Lowry base and Lewis base

  • A Lewis acid is an electron pair acceptor 

  • A hydroxide ion can only act as a Lewis base

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71 mark

Which compound will react most readily by an SN2 mechanism?

  • (CH3)3CBr

  • CH3CH2CH2CH2Cl

  • CH3CH2CH2CH2Br

  • (CH3)3CCl

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81 mark

An alkene, X, undergoes electrophilic addition with hydrogen bromide to form a halogenoalkane, Y, as the minor product. 

The halogenoalkane, Y , can react with sodium hydroxide in aqueous conditions to form butan-1-ol. 

What is the correct identity of the alkene, X? 

  • 2-methylpropene

  • But-1-ene

  • But-2-ene 

  • Pent-1-ene

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91 mark

Benzene can undergo nitration to form nitrobenzene. Which of the following statements is not correct?

  • Concentrated nitric acid acts as a base 

  • A nitronium ion acts as an electrophile 

  • HSO4- is produced in the formation of the electrophile 

  • Aluminum chloride is required as a catalyst for the reaction 

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101 mark

The synthesis of ethyl butanoate can be carried out in three steps:

                                         I                   II                      III

                        C4H9Br   →  C4H9OH  →  C3H7COOH  →  C3H7COOC2H5  

What is the correct classification of the steps?

 

I

II

III

A

substitution

oxidation

condensation

B

addition

substitution

condensation

C

oxidation

substitution

condensation

D

substitution

oxidation

substitution

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111 mark

Which of the following reactions produces only pentan-2-ol?

  • Water and pent-1-ene

  • 1-bromopentane and ethanolic NaOH

  • Water and pent-2-ene

  • 2-bromopentane and ethanolic NaOH

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121 mark

Which compound could be X in this two step reaction pathway?

C3H8 → X  → C3H7OH

  • C2H5CN

  • C3H7Cl

  • C3H6Cl2

  • C2H5COOH

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