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

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First teaching 2023

First exams 2025

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Electron Pair Sharing Reactions (SL IB Chemistry)

Exam Questions

1 hour23 questions

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Electron Pair Sharing Reactions

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Electron Pair Sharing Reactions

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1a1 mark

A reaction scheme for propene is shown below.

10-2-ib-sl-sq-easy-q1a-reaction-scheme-of-propene

State the condensed structural formula of propene.

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1b3 marks

State the IUPAC names for compounds A, B and C shown in the reaction scheme in part (a)

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1c3 marks

Propene will also react to form an alcohol. State the reagents and conditions required for the formation of an alcohol from propene. 

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1d1 mark

State the colour change when compound B is formed from propene. 

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1e2 marks

Propene can form polypropene. Draw the repeating unit that will be formed via the addition polymerisation of propene. 

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2a2 marks

The structure of but-1-ene is shown below. But-1-ene IB SL SQ 10.2 E Q5a

Draw and state the name of the secondary halogenoalkane formed when but-1-ene reacts with HCl. 

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2b2 marks

Explain why halogenoalaknes are more reactive than alkanes.

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2c3 marks

State the reagents and conditions required for the formation of propan-1-ol from 1-bromopropane. 

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2d1 mark

The type of reaction outlined in part (c) is nucleophilic substitution. State the meaning of the term nucleophile. 

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3a2 marks

Define the term nucleophile. 

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3b2 marks

Explain why the hydroxide ion, OH- , is a stronger nucleophile than water. 

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4a3 marks

Propan-1-ol can be synthesised from alkene P in the following synthetic route:

       alkene P rightwards arrow with Step space 1 on top halogenoalkane Q rightwards arrow with Step space 2 on top propan-1-ol

i)
State the identity of halogenoalkane Q.

[1]

ii)
Give the reagents and conditions needed for Step 2.

[2]

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4b2 marks

Give the name and structure of alkene P.

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4c3 marks

Give a reagent that could be used to convert P to Q and outline why this synthesis of propan-1-ol might not be very efficient.

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4d4 marks

This question is about alkene P and Step 1.

i)
Give the empirical formula of P.

[1]

ii)
Give the reagents and conditions needed for Step 1.

[2]

iii)
State the type of reaction mechanism.

[1]

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13 marks

An aromatic organic compound with molecular formula C7H8 reacts with bromine in the presence of UV light to produce a compound with molecular formula C7H7

i)
Name the type of reaction taking place.
[1]
ii)
Deduce the structures of the reactant and product.
[1]
iii)
Give the formula of an additional organic product that could be obtained in the reaction.
[1]

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22 marks

Sketch a graph to indicate the change in pH during a titration of 25.0 cm3 of 0.100 mol dm-3 hydrochloric acid, HCl (aq) , with 0.100 mol of ammonia, NH3 (aq).

q1c_18-1_ib_hl_medium_sq

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3a1 mark

The starting materials for many products are alkenes such as propene.

State the type of reaction that occurs when propene is converted into chloropropane.

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3b1 mark

Two possible isomeric products can be formed in the conversion of propene to chloropropane. 

State the type of isomerism that is exhibited by these chloropropane products.

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43 marks

Kekulé proposed the following structure of benzene.q3a_20-1_ib_hl_medium_sq

Discuss the physical and chemical evidence to suggest that the Kekulé structure of benzene is incorrect.

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5a1 mark

Butan-1-ol can also be formed by the catalytic reduction of butanal. State the reagents for this reduction to occur

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5b1 mark

State the reagent required to reduce butanoic acid to butan-1-ol. 

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5c1 mark

Using your answer to (b), write the equation for the reduction reaction of butanoic acid.

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62 marks

1-bromobutane and 2-bromo-2-methylpropane are isomers. State the type of structural isomerism that they exhibit, explaining your reasoning.

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1a2 marks

The following scheme shows reactions of Compound A. 

10-2-ib-sl-sq-hard-q4a-reaction-scheme
i)
Deduce the structural formula of compound A.
[1]
ii)
Apply IUPAC rules to name compound B.
[1]

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1b2 marks

Reaction 1 forms an alcohol when reacted with concentrated sulfuric acid, H2SO4 and steam. 

i)
State the conditions required for this reaction.
[1]

ii)
Deduce the structure of the intermediate in this reaction. 
[1]

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1c3 marks

Butan-2-ol can also be directly formed from a halogenoalkane. 

i)
State the name of of the type of reaction occurring in this conversation.
[2]
ii)
State the conditions for this reaction. 
[1]

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1d1 mark

Identify the structure of the repeating unit of poly(but-2-ene).

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1e1 mark

Compound A reacts with hydrogen bromide to form compound C. A student suggested a possible formula of compound C is CH2(Br)CH2CH2CH3.

State whether the student is correct and justify your answer. 

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2a3 marks

A complex of cobalt has the following composition by mass:

Co, 21.98%; N, 31.35%; H, 6.81%; Cl, 39.86%

i)
Calculate the empirical formula of this complex.
[2]

ii)
The formula of this cobalt complex can be expressed in the form [Co(L)m]x+(Cl−)n.
Suggest the chemical formula of [Co(L)m]x+.

[1]

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2b2 marks

Nickel(II) forms a complex ion with water, [Ni(H2O)6]2+

i)
Outline how the bond is formed between Ni2+ and H2O during the formation of the complex.

[1]

ii)        State the geometry of the complex formed.

[1]

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