- 1. Which statement best describes the process of oxidation?
A) gain of electrons
B) loss of oxygen
C) loss of electrons
D) addition of hydrogen
- 2. Determine the oxidation number of chromium in the compound K2Cr₂O7
A) +5
B) +3
C) +6
D) +2
- 3. X forms a trivalent cation while Y forms a divalent anion. The dissociation of a compound of X and Y can be written as
A) X2Y3 →2X3+ + 3Y2-
B) X3Y₂ → X3+ + Y2-
C) XY → X3+ + Y2-
D) 3XY₂ → X3+ + Y2-
- 4. What is the change in the oxidation number of Mn in the following reaction? MnO4-(aq) + 8H- (aq) + 5e- →Mn2+ + 4H2O (l)
A) +8 to +2
B) +7 to +2
C) -4 to +2
D) -1 to +2
- 5. What quantity of electrons (in mole) is lost when one mole of ion (II) ions is oxidised to ion (III) ions.
A) 2 moles
B) 1 mole
C) 4 moles
D) 3 moles
- 6. H2S (g) + Cl2(g) → 2HCl(g) + S(s)
The oxidising agent in the reaction above is - -
A) S
B) H₂S
C) HCl
D) Cl₂
- 7. What is the value of x is the following equation? MnO4- + 4H+ + xe- → MnO2 + 2H₂O
A) 7
B) 4
C) 3
D) 2
- 8. The collective name for elements in the group seven is the ----------
A) halogens
B) alkalin-earth metals
C) alkali metals
D) inert gases
- 9. The position of an element on the periodic table is determined by........
A) the number of protons in its atom.
B) its density
C) its atomic radius
D) its relative atomic mass
- 10. Lithium and sodium show similar chemical properties. Which of the following statements is not true about the two elements?
A) They are in the same period in the periodic table
B) Both exist in the +1 oxidation state in their compound
C) They have equal number of electrons in their outermost shells
D) They belong to the same group in the periodic table
- 11. The electronic configuration of elements X, Y and Z are as follows X- Is2 2s2 2p6 3s2 Y - Is² 2s² 2p6 3s2 3p¹ Z-Is² 2s²2p6 3s2 3p2 To which period do X, Y and Z belong?
A) 3
B) 4
C) 2
D) 1
- 12. Use the diagram above to answer the following question. The letters indicating elements which exist as monoatomic gases are
......
A) R and S
B) X and R
C) P and Q
D) T and W
- 13. Use the diagram above to answer the following question. What letter represents an element that undergoes covalent bonding?
A) S
B) T
C) Q
D) R
- 14. Zinc will displace copper ions from
solution but silver will not because in the electrochemical series
.....
A) silver is higher than zinc and copper
B) zinc is higher than copper whereas silver is lower than copper
C) silver is higher than copper but lower than zinc
D) zinc is lower than copper and silver
- 15. If an atom of aluminium is represented as Al, what mass of aluminium will be liberated by 0.6F of electricity? [1F = 96,500Cmol-¹ and Al = 27g)
A) 8.1g
B) 2.7g
C) 16.2g
D) 5.4g
- 16. Faraday's first law of electrolysis can be expressed mathematically as
A) Q = It
B) Q =EIt
C) m = ¹/It
D) m =EIt
- 17. In the diagram above X and Y are known as -
A) carbon
B) metal plates
C) electrodes
D) conductors
- 18. Calculate the quantity of electricity passed when 0.4A flows for 1 hour 20mins through an electrolytic cell.
A) 32c
B) 3840c
C) 1920c
D) 4800c
- 19. Which of the following ions will migrate to the cathode during electrolysis?
A) Zinc ions
B) Sulphide ions
C) Tetraoxsulphate (VI) ions
D) Chloride ions
- 20. What current in amperes will deposit 2.7g of aluminium in 2 hours?
[Al = 27, F = 96500C mol-¹]
A) 4
B) 32
C) 16
D) 8
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