>OBAFEMI AWOLOWO UNIVERSITY CHEMISTRY PAST QUESTIONS 2009

>CHEMISTRY
OBAFEMI AWOLOWO UNIVERSITY
ILE-IFE 2009
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1. Stainless steel is an alloy of
A. carbon, iron and lead
B. carbon, iron and chromium
C. carbon, iron and copper
D. carbon, iron and silver
E. carbon and iron only

2. Tetraoxosulphate(Vl) ions are final test using
A. acidified silver nitrate
B. acidified barium chloride
C. lime-water
D. dilute hydrochloric acid
E. acidified hard nitrate

3. T he flame used by welders in cutting metal is
A. Butane gas flame
B. Acetylene hydroflame
C. Kerosene flame
D. Oxy-acetylene
E. Oxygen flame

4. W hich of the following has the lowest pH value ?
A. Calcium carbonates
B. Sodium trioxocarbonate(lV)
C. Hydrochloric acid
D. Ethaonic acid
E. Hydrocarbon acid

5. T he function of sulphur during the vulcanization of rubber is to
A. act as catalyst for the polymerization of rubber molecules
B. convert rubber from thermosetting to thermo plastic polymer
C. form chains which bind rubber molecules together
D. break down rubber polymer molecules
E. shorter the chain length of rubber polymer

6. W hich of the following physical properties decreases across the periodic table
A. ionization potential
B. electron affinity
C. electron negativity
D. atomic radius
E. electro-positive reaction

7. M ortal is NOT used for under water construction because
A. It hardens by loss of water
B. Its hardening does not depend upon evaporation
C. It requires concrete to harden
D. It will be washed away by the flow of water
E. It softens when exposed

8. W hich of these will dilute in HCl ? Mg, Fe, Pb and Cu
A. All the metals
B. Mg, Fe and Cu
C. Mg, Fe and Pb
D. Mg and Fe only
E. Mg only

9. W hat volume of 0.50M H 2 SO 4 will exactly neutralize 20Cm 3 of 0.1M NaOH solution
A.
2.0cm 3
B.
5.0cm 3
C.
6.8cm 3
D.
8.3cm 3
E.
10.4cm 3

10. W hich of the following roles does sodium chloride play in soap preparation ? It
A. reacts with glycerol
B. purifies the soap
C. accelerates the decomposition of the fat and oil
D. seprates the soap from glycerol
E. converts the fat acid to its sodium salt

11. A gas that can behave as a reducing agent towards chlorine and as an oxidizingagent towards hydrogen sulphide is
A. O 2
B. NO
C. SO 2
D. NH 3
E. CO 2

12. Consequent members of an alkane homogenous series differ by
A. CH
B. CH 2
C. CH 3
D. CH 3
E. C n H 2n+2

13. H ow many isomers can be formed from organic compounds with the formula C 3 H 8 O
A. 2
B. 3
C. 4
D. 5
E. 1

14. A n element with atomic number twelve is likely to be
A. electrovalent with a valency of 1
B. electrovalent with a valency of 2
C. covalent with a valency of 2
D. covalent with a valency of 4

15. S tarch can be converted to ethyl alcohol by
A. distillation
B. fermentation
C. isomerization
D. cracking
E. osmosi

16. In the haber process for the manufacture of ammonia, finely divided iron is used as
A. an ionizing agent
B. a reducing agent
C. a catalyst
D. a dehydrating agent
E. an oxidizing agent

17. W hen platinum electrodes are used during the electrolysis of copper(ll)tetraoxosulphates(Vl)solution, the solution get progressively
A. acidic
B. basic
C. neutral
D. amphoteric

18. At STP how many litres of hydrogen can be obtained from the reaction of 500cm 3 of 0.5M H 2 SO 4 excess zinc metal
A. 22.4dm 3
B. 11.2dm 2
C. 65dm 2
D. 5.6dm 3
E. 0.00dm 3

19. W hich of the following is used in fire extinguishers
A. carbon(ll)
B. Carbon (Vl) oxide
C. Sulphur (lV) oxide
D. ammonia
E. Sulphur(lll)oxide

20. W hich of the following compound is not formed by the action of chlorine on methane
A. CH 3 Cl
B. C 2 H 5 Cl
C. CH 2 Cl 2
D. CHCl 3
E. CH 4 Cl

21. W hich of the following is an acid salt?
A. NaHSO 4
B. Na 2 SO 4
C. CH 3 CO 3
D. Na 2 S 2
E. C 2 H 5

22. Nitrogen can be best obtained from a mixture of oxygen and nitrogen by passing the mixture over
A. potassium hydroxide
B. heated gold
C. heated magnesium
D. heated phosphorus
E. calcium chloride

23. A n element that can exist in two or more different structure forms which posses the same chemical properties is said to exhibit
A. polymerism
B. isotopy
C. isomorphism
D. isomerism
E. allotropy

24. W hich of the following is NOT the correct product formed when the parent metal is heated in air?
A. Calcium oxide (Cao)
B. sodium oxide (Na 2 O)
C. copper(ll)oxide (CuO)
D. aluminium oxide (Al2O3)

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