February/March 2026 Paper 22

2026 · 4 questions · 39 parts · 60 marks

0/60 marks

0Correct0Partial0Wrong39Unattempted

Filters0 active

Questions

Select a part to jump to its question

3(a)HalogenoalkanesEasy1 mark

Secondary halogenoalkanes are important building blocks in organic chemistry. 2-chlorobutane is an example of a secondary halogenoalkane.

Figure 3.1, the skeletal structural formula of 2-chlorobutane: a four-carbon zigzag chain with a Cl atom bonded to the second carbon from the left.

Explain why 2-chlorobutane is classified as a secondary halogenoalkane.

Answer

0 words

3(b)(i)Structural Geometric IsomerismMedium1 mark

2-chlorobutane can be formed by the electrophilic addition of HCl to different isomers of C

_{4}

_{8}

. Compound A is one of these isomers.

Figure 3.2, the skeletal structural formula of compound A, cis-but-2-ene: a four-carbon chain, CH$_{3}$-CH=CH-CH$_{3}$, drawn folded back on itself so both methyl-bearing ends point to the same side of the C=C double bond.

Draw a structural isomer of A that can also form 2-chlorobutane when it reacts with HCl.

Draw with the mouse or a finger.

3(b)(ii)Structural Geometric IsomerismMedium2 marks

Draw and give the systematic name of the geometrical isomer of A.

Draw with the mouse or a finger.

3(b)(iii)Structural Geometric IsomerismMedium2 marks

State and explain the origin of geometrical isomerism in alkenes.

Answer

0 words

3(c)(i)AlkanesEasy1 mark

Butane, C

_{4}

_{10}

, reacts with Cl

_{2}

in the presence of ultraviolet light to form 2-chlorobutane, which has molecular formula C

_{4}

_{9}

Cl.

C_{4} H_{10} + C l_{2} \to C_{4} H_{9} C l + H C l

Name the mechanism of this reaction.

3(c)(ii)AlkanesMedium2 marks

Complete the reaction scheme given to show the formation of 2-chlorobutane. You may use molecular formulas in your answer.

initiation C l_{2} \to 2 C l^{∙}

propagation C_{4} H_{9}^{∙} + C l_{2} \to C_{4} H_{9} C l + C l^{∙}

Propagation

0 words

Termination

0 words

3(d)HalogenoalkanesMedium2 marks

The rates of hydrolysis of three secondary halogenoalkanes, B, C and D, are compared.

Figure 3.3, the skeletal structural formulae of three secondary halogenoalkanes: B, a four-carbon chain with Cl on the second carbon; C, the same chain with Br on the second carbon; D, the same chain with I on the second carbon.

Each halogenoalkane is dissolved in ethanol and reacted with AgNO

_{3}

(aq). Identify the order of the rates of hydrolysis of compounds B, C and D. Explain your answer.

Order, fastest to slowest (e.g.

X > Y

> Z)

Explanation

0 words

3(e)AlcoholsMedium3 marks

The organic product of hydrolysis of each of B, C and D is butan-2-ol. Complete Table 3.1 to give details of some typical chemical reactions of butan-2-ol.

Draw with the mouse or a finger.