May/June 2026 Paper 42

2026 · 9 questions · 56 parts · 100 marks

0/100 marks

0Correct0Partial0Wrong56Unattempted

Filters0 active

Questions

Select a part to jump to its question

Finish set

1(a)(i)1(a)(ii)1(b)(i)1(b)(ii)1(c)1(d)(i)1(d)(ii)1(e)1(f)(i)1(f)(ii)1(g)1(h)

–/20 mks

2(a)2(b)2(c)2(d)(i)2(d)(ii)2(d)(iii)

–/10 mks

3(a)(i)3(a)(ii)3(a)(iii)3(b)3(c)

–/10 mks

4(a)4(b)4(c)

–/6 mks

5(a)5(b)(i)5(b)(ii)5(b)(iii)5(c)

–/11 mks

6(a)(i)6(a)(ii)6(b)6(c)(i)6(c)(ii)6(d)6(e)(i)6(e)(ii)

–/14 mks

7(a)(i)7(a)(ii)7(b)(i)7(b)(ii)7(c)7(d)(i)7(d)(ii)

–/11 mks

8(a)8(b)(i)8(b)(ii)8(b)(iii)8(c)

–/8 mks

9(a)9(b)(i)9(b)(ii)9(c)(i)9(c)(ii)

–/10 mks

8(a)Nmr Spectroscopy Structure ElucidationEasy1 mark

Give the full name of the substance used in NMR spectroscopy as the standard for chemical shift measurements.

8(b)(i)Nmr Spectroscopy Structure ElucidationMedium1 mark

Compound

K

is analysed by carbon-13 NMR and proton (

^{1}

H) NMR spectroscopy in D

_{2}

Figure 8.1, compound $K$: a central –C(=O)–NH– amide linking an isopropyl group (on the carbonyl side, (CH$_{3}$)$_{2}$CH–) to a 2-chloroethyl group (on the nitrogen side, –CH$_{2}$CH$_{2}$Cl) — N-(2-chloroethyl)-2-methylpropanamide.

Predict the number of peaks in the carbon-13 NMR spectrum of

K

Number of peaks

8(b)(ii)Nmr Spectroscopy Structure ElucidationMedium2 marks

The proton (

^{1}

H) NMR spectrum of

K

in D

_{2}

O shows four peaks, for the proton environments labelled w, x, y and z on the structure of

K

in Figure 8.2.

Figure 8.2, the structure of $K$ with its four distinct proton environments labelled: ‘w’ for the two equivalent CH$_{3}$ groups, ‘x’ for the CH of the isopropyl group, ‘y’ for the CH$_{2}$ next to the amide nitrogen, and ‘z’ for the CH$_{2}$ next to the Cl.

Identify the splitting pattern for each of the proton environments w, x, y and z.

Proton environment w

Proton environment x

Proton environment y

Proton environment z

8(b)(iii)Nmr Spectroscopy Structure ElucidationMedium2 marks

Figure 8.2, the structure of $K$ with its four distinct proton environments labelled w, x, y and z (see 8(b)(ii)).

A separate sample of

K

is dissolved in CDCl

_{3}

and analysed using proton (

^{1}

H) NMR spectroscopy. The proton (

^{1}

H) NMR spectrum of

K

dissolved in CDCl

_{3}

contains one more peak than the spectrum of

K

dissolved in D

_{2}

O. Explain why there is one more peak, and suggest the chemical shift range in which it occurs.

Explanation

0 words

Chemical shift range

δ

8(c)Acyl Chlorides AmidesMedium2 marks

Compound

K

reacts with an excess of hot NaOH(aq).

Figure 8.3, compound $K$: a central –C(=O)–NH– amide linking an isopropyl group (on the carbonyl side, (CH$_{3}$)$_{2}$CH–) to a 2-chloroethyl group (on the nitrogen side, –CH$_{2}$CH$_{2}$Cl) — N-(2-chloroethyl)-2-methylpropanamide.

Table 8.2 shows typical

^{1}

H NMR chemical shift ranges for different proton environments.

environment of proton	example	chemical shift range δ / ppm
alkane	–CH $_{3}$ , –CH $_{2}$ –, >CH–	0.9–1.7
alkyl next to $C = O$	CH $_{3}$ – $C = O$ , –CH $_{2}$ – $C = O$ , >CH– $C = O$	2.2–3.0
alkyl next to aromatic ring	CH $_{3}$ –Ar, –CH $_{2}$ –Ar, >CH–Ar	2.3–3.0
alkyl next to electronegative atom	CH $_{3}$ –O, –CH $_{2}$ –O, –CH $_{2}$ –Cl	3.2–4.0
attached to alkene	=CHR	4.5–6.0
attached to aromatic ring	H–Ar	6.0–9.0
aldehyde	HCOR	9.3–10.5
alcohol	ROH	0.5–6.0
phenol	Ar–OH	4.5–7.0
carboxylic acid	RCOOH	9.0–13.0
alkyl amine	R–NH–	1.0–5.0
aryl amine	Ar–NH $_{2}$	3.0–6.0
amide	RCONHR	5.0–12.0

The products are isolated from the reaction mixture at pH 10. Draw the structures of the two organic products of the complete alkaline hydrolysis of

K

Draw with the mouse or a finger.