This question was not well attempted by the candidates and the performance was poor. The
candidates had difficulty in drawing the structures of the organic compound.
Also most candidates had low performance because they do not properly understand the
rubrics of 4(d).
The expected answers were:
(a) (i) Structural isomers are compounds with the same molecular formula but different
arrangement of constituent atoms/or different structures.
(ii) CH3 CH2 CH2 CH2 OH, CH3 CHCH2 OH
CH3 CHCH2 CH3 CH3
OH (CH3) 3- C- OH
(iii) (CH3)3 C-OH
(b) (i) C5 H12 + Cl2 light C5H11 Cl + HCl
(ii) H H H H H
H C C C C C Cl
H H H H H
(iii) Light acts as catalyst.
(iv) Pentane C5H12 would come out first.
Pentane has a lower molar mass (72) as compared to chloropentane
(C5H11 Cl) (86.5).
Hence weaker inter molecular forces/van der Waals’ forces.
(v) C4 H6 Cl2
(c) (i) H H H H
H C C C C H
H
OH H
H C H
H
3-methyl butan–2–ol/ 3- methyl-2-butanol
(ii) CH3 - CH - COOH
OH
2–hydroxypropanonic acid
(d) (i) I CH3 - CH COOH
+ NH3
II CH3 - CH –COO-
NH2
(ii) % N = 0. 0313 x 100
0. 309
= 10. 1 %
% O = 100 – (60.5 + 6.5 + 10.1)
= 22. 9
C H N O
60.5 6.5 10.1 22.9
12 1 14 16
5.04 6.5 0.72 1 43
5.04 6.5 0.72 1.43
0.72 0.72 0.72 0.72
7 9.027 1 1.99
Empirical formula
C7 H9 NO2
