- 1. Consider the reaction represented by xIO3- + yI- + 6H+ --------> 2H₂O + 3₂ what are the values of x, y and z respectively?
A) 5,5,3
B) 3, 1, 5
C) 5, 3, 1
D) 1, 5, 3
- 2. Which statement best describes the process of oxidation?
A) gain of electrons
B) loss of electrons
C) loss of oxygen
D) addition of hydrogen
- 3. Determine the oxidation number of chromium in the compound K2Cr₂O7
A) +6
B) +3
C) +2
D) +5
- 4. 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) X3Y₂ → X3+ + Y2-
B) X2Y3 →2X3+ + 3Y2-
C) XY → X3+ + Y2-
D) 3XY₂ → X3+ + Y2-
- 5. What is the change in the oxidation number of Mn in the following reaction? MnO4-(aq) + 8H- (aq) + 5e- →Mn2+ + 4H2O (l)
A) -1 to +2
B) +7 to +2
C) +8 to +2
D) -4 to +2
- 6. What quantity of electrons (in mole) is lost when one mole of ion (II) ions is oxidised to ion (III) ions.
A) 1 mole
B) 3 moles
C) 4 moles
D) 2 moles
- 7. H2S (g) + Cl2(g) → 2HCl(g) + S(s)
The oxidising agent in the reaction above is - -
A) S
B) Cl₂
C) H₂S
D) HCl
- 8. Cu₂S(s) +O2 (g) → 2Cu(s) +SO2(g)
What is the change in the oxidation number of copper in the reaction above?
A) +1 to O
B) O to +2
C) O to +1
D) +2 to +1
- 9. 3Cu2 + 8HNO3(aq) → 3Cu(NO3)_2(aq) + 4H2O(l) + 2NO(g)
In the equation above, copper is
.....
A) a reducing agent
B) an electron acceptor
C) an oxidising agent
D) a base
- 10. What is the value of x is the following equation? MnO4- + 4H+ + xe- → MnO2 + 2H₂O
A) 4
B) 2
C) 7
D) 3
- 11. The oxidation number of X in XO4³- is
........
A) +2
B) +5
C) +3
D) +4
- 12. The collective name for elements in the group seven is the ----------
A) halogens
B) inert gases
C) alkali metals
D) alkalin-earth metals
- 13. The position of an element on the periodic table is determined by........
A) its density
B) its relative atomic mass
C) the number of protons in its atom.
D) its atomic radius
- 14. Lithium and sodium show similar chemical properties. Which of the following statements is not true about the two elements?
A) They have equal number of electrons in their outermost shells
B) They are in the same period in the periodic table
C) Both exist in the +1 oxidation state in their compound
D) They belong to the same group in the periodic table
- 15. 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) 2
C) 1
D) 4
- 16. Which of the following statements about the elements, Na, Mg, Al and Si is / are true?
I. They are all in period 3 of the periodic table II. Mg is more electropositive than Si
III. Electropositivity decreases from Na to Si IV. Si is the most electropositive element.
A) I only
B) I and IV only
C) I, II, III and IV
D) I, II and III only
- 17. The element with the electronic
configuration Is2 2s2 2p6 3s2 3p6 3d2 4s² is a/an
A) transition metal
B) alkaline earth metal
C) group IV element.
D) group II element
- 18. Li, Na, and K are in the same group in the periodic table because they have the same. ........
A) ionisation energy
B) electronic configuration
C) number of valence electrons
D) atomic radius
- 19. Use the diagram above to answer the following question. The letters indicating elements which exist as monoatomic gases are
......
A) X and R
B) R and S
C) T and W
D) P and Q
- 20. Use the diagram above to answer the following question. What letter represents an element that undergoes covalent bonding?
A) Q
B) R
C) S
D) T
- 21. Use the diagram above to answer the following question. Which letter represents a halogen?
A) S
B) R
C) X
D) P
- 22. What is the most probable group of an element which is a soft, silvery-white solid and reacts violently with water?
A) Group 1
B) Group 6
C) Group 4
D) Group 7
- 23. P, Q, R and S are metals in the same group in the periodic table but in periods 3,4,5 and 6 respectively. Which of them loses electrons least readily?
A) Q
B) S
C) R
D) P
- 24. 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) silver is higher than copper but lower than zinc
C) zinc is higher than copper whereas silver is lower than copper
D) zinc is lower than copper and silver
- 25. 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) 16.2g
C) 2.7g
D) 5.4g
- 26. If 20cm³ of H₂ was liberated at the cathode during the electrolysis of dilute tetraoxosulphate (VI) acid, what volume of O₂ would be liberated at the anode
.....
A) 10cm³
B) 20cm³
C) 40cm³
D) 5cm³
- 27. Faraday's first law of electrolysis can be expressed mathematically as
A) m =EIt
B) Q =EIt
C) Q = It
D) m = ¹/It
- 28. In the diagram above X and Y are known as -
A) carbon
B) electrodes
C) conductors
D) metal plates
- 29. When an electric current is passed through a solution containing dilute tetraoxosulphate (VI) acid, 190cm³ of hydrogen gas is evolved. If the measurements were made at 26°C and 736 mmHg, what is the volume of hydrogen at s.t.p
A) 179.1cm³
B) 201.5cm³
C) 164 cm³
D) 168cm³
- 30. In the electrolysis electrolysis of aluminium chloride, 10A of electricity was passed for 96.5sec. Calculate the mass in gram of aluminium deposited [Al = 27, Cl=35.5, F = 96500C]
A) 0.09
B) 0.45
C) 0.21
D) 0.27
- 31. Calculate the quantity of electricity passed when 0.4A flows for 1 hour 20mins through an electrolytic cell.
A) 1920c
B) 32c
C) 4800c
D) 3840c
- 32. The product at the cathode when copper(II) tetraoxosulphate (VI) solution is electrolysed using copper electrodes is
A) sulphur
B) copper
C) hydrogen
D) oxygen
- 33. Calculate the quanity of electricity required to deposit 64.0g of copper from molten copper (II) chloride. [Cu = 64, F = 96500c]
A) 6.18 x 106C
B) 9.65 x 104C
C) 3.09 x 106C
D) 1.93 x 105C
- 34. If the overall reaction in a cell is Mg(s) + Pb2+ (aq) → Pb(s) + Mg2+(aq) schematic representation would be its
A) Mg(aq)/Mg2+(s) // Pb2+(s) / Pb(aq)
B) Pb2+(aq)/Pb(s) Mg(s)/Mg2+ (aq)
C) Mg(aq)/Mg2+ (aq) // Pb2+(aq) /Pb (aq)
D) Mg(s)/Mg2+(aq) // Pb2+ +(aq) / Pb(s)
- 35. Which of the following ions will migrate to the cathode during electrolysis?
A) Zinc ions
B) Tetraoxsulphate (VI) ions
C) Chloride ions
D) Sulphide ions
- 36. The common feature of reactions at the anode is that
...
A) the electrode dissolves
B) electrons are consumed
C) oxidation is involved
D) ions are reduced
- 37. What amount of mercury would be liberated if the same quantity of electricty that liberates 0.65g of Zinc is applied? [Zn = 64.5g]
A) 4.02g
B) 2.01g
C) 1.00g
D) 8.04g
- 38. What current in amperes will deposit 2.7g of aluminium in 2 hours?
[Al = 27, F = 96500C mol-¹]
A) 8
B) 4
C) 16
D) 32
- 39. A metal M displaces zinc from zinc chloride solution. This shows that ....
A) zinc is above hydrogen in the series
B) M is more electropositive than zinc.
C) M is more electronegative than zinc
D) electrons flow from zinc to M
- 40. What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution? [F = 96500Cmol']
A) 72375 coulombs
B) 96500 coulombs
C) 48250 coulombs
D) 24125 coulombs
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