(a)(i) Structural Isomers of C${}_4$H${}_4$

(ii) (I)Tertiary(3°)alkanol.

(II) Primary (1°)alkanol.

(III) Secondary (2°) alkanol



(b)(i)

(I) CH${}_3$CH${}_2$COOK, H${}_2$

(II) CH${}_3$CH${}_2$COOC${}_4$H${}_9$ H${}_2$O

(III) CH${}_3$CH${}_2$CH${}_2$COOH

(ii) Major products in (b)(i) (1) — Potassuim propanoate (II) — Butyl propanoate (III) — Butanoic acid



(C)(i) % carbon by mass = 100 – 14.3 (l) = 85.7%

Ratio of atoms = $\frac{C}{\frac{85.7}{12.0}}$ = 7.1415; $\frac{H}{\frac{14.3}{1.0}}$ = 14.3

Divide by smaller number = $\frac{7.1415}{7.1415}$ = 1; $\frac{14.3015}{7.1415}$ = 2

Empirical Formular = CH${}_2$



(i) 2.24dm${}^3$ = 7.0g of R

22.4dm${}^3$ = $\frac{7.0}{2.24}$ x 22.4 = 70gmol${}^1$

OR

Molar volume of gas = 22.4 dm${}^3$ at s.t.p 22.4

22.4 dm${}^3$ gas = 1 mole

22.4 dm${}^3$ = $\frac{2.24}{22.4}\times 1$ = 0.1 mol

But numbers of moles = 0.1

Mr = $\frac{7}{0.1}$ = 70gmol${}^1$

Molecular formular = C${}_5$H${}_{10}$

(CH_2)n = 70

14n = 70

n = $\frac{70}{4}$ = 5



(d) The occurence of / existence of / condition whereby compounds with the same molecular formula have different structural formulae.