EXAM BOSS RUNZ centre

*WAEC GCE CHEMISTRY*

*NUMBER FIVE*

(5a)
(i)2NaOH + Cl_2 NaCl + NaClO + H2O
(ii)Cl_2 + H2O HOCl + HCl

(5aii)
(I)Chlorine: Gas
(II) Fluorine: Gas
(III) Astatine: Solid

(5aiii)
The strength of Van der Waal's forces increases down the group due to the increase in atomic size and polarizability.

(5bi)
(i)Low temperature
(ii)High pressure

(5bii)
The choice of conditions is governed by Le Chatelier's principle, which states that a system at equilibrium will adjust to counteract any changes in concentration, temperature, or pressure.

(5biii)
(i) For fertilizer production.
(ii)For cleaning agent
(iii)For Industrial applications

(5ci)
(i)High electrical conductivity
(ii)Ductility
(iii)Resistance to corrosion

(5cii)
(i)Oxidizing properties.
(ii)Antimicrobial activity.

(5di)
(i)For Construction.
(ii)It is use as an food and nutrition for humans.
(iii)It is use for manufacturing products, including paper, glass, and ceramics.

(5dii)
(i)Coke
(ii)Coal tar

*WAEC GCE CHEMISTRY OBJ*

1. B — hygroscopic. (CaCl₂ is used as a desiccant because it absorbs moisture.)

2. A — Fructose. (Fructose is a monosaccharide; the others are disaccharides.)

3. C — molecule. (A molecule is the smallest particle that retains the chemical properties.)

4. C — 2,2,4-trimethylpentane. (Structure corresponds to CH₃–C(CH₃)₂–CH₂–CH(CH₃)–CH₃.)

5. A — working capital. (Siting concerns are physical/locational; working capital is a financial factor.)

6. C — sublimation. (Conversion from solid to gas.)

15. The silver halides are all insoluble in water except

✔ A. AgF
AgF is soluble; AgCl, AgBr, and AgI are insoluble.

16. The oxidation number of chromium in Cr₂O₇²⁻ is

✔ B. +6
Let oxidation state of Cr = x:
2x + 7(–2) = –2 → 2x – 14 = –2 → 2x = 12 → x = +6.

17. Which of the following statements is correct?
✔ B. ΔH₁ < ΔH₂
Formation of water releases more energy (more exothermic) than formation of hydrogen peroxide.

18. At the endpoint of a strong acid vs strong base titration, the solution is

✔ C. neutral
pH ≈ 7.

19. The following substances are covalent solids except
✔ D. CuO
CuO is ionic; the others form covalent networks.

20. Amount of sodium in 53 g Na₂CO₃
Molar mass = 106 g/mol
53 g = 0.5 mol Na₂CO₃ → Na atoms = 2 × 0.5 = 1.0 mol
✔ D. 1.00 mol

21. Gases have high compressibility because the molecules
✔ B. are widely spaced.

22. The minimum energy required for a reaction to take place is
✔ A. activation energy

WHATSAPP US:: 07036103137
More coming