COLLIGATIVE, REDOX AND ELECTROCHEMICAL CELL TEST

1. A solution of K2CrO4 is 10.0% by mass and the mass of solution is 194 grams. The mol fraction of solute is …. (Ar: K = 39, Cr = 52, O = 16, H = 1).
a. 0,01
b. 0,02
c. 0,05
d. 0,10
e. 0,20
2. The molality of a 4.6% by mass aqueous solution of ethanol (CH3CH2OH) is …. (Ar: C = 12, H = 1, O = 16).
a. 0,15
b. 1,05
c. 1,50
d. 2,05
e. 2,10
3. A solution is prepared from mixing 18 g of solid glucose, C6H12O6 in 200 g of water and 11,1 g of CaCl2 in 400 g of water at 25oC. The vapor pressure of pure water is 24 mmHg at 25oC. What is the vapor pressure of this solution? Ar C = 12; H = 1; O = 16; Ca = 40; Cl = 35,5.
a. 12 mmHg
b. 15 mmHg
c. 18 mmHg
d. 20 mmHg
e. 21 mmHg
4. Dissolving 1 mol of KCl in 1000 grams of H2O affects ….
a. the boiling point of the H2O, only
b. the freezing point of the H2O, only
c. the boiling point of solution, only
d. both the boiling point and the freezing point of the H2O
e. neither the boiling point nor the freezing point of the H2O
5. A solution contains 10,6 g of M2X (Mr = 106) in 500 g of water. If the melting point of this solution – 0,10C and Kf = 1,860C/m , ionization degree, α of M2X is ….
a. 0,6
b. 0,7
c. 0,75
d. 0,8
e. 0,9
6. A solution consists of 3 grams of urea (Mr = 60) in 100 grams of water. This solution boils at the same temperature with a solution which contains of 18 g X (a non electrolyte substance) in 200 g of water. Mr of X is ….
a. 90
b. 120
c. 180
d. 200
e.240
7. Refer to the phase diagram below:

Which point could represent a boiling point for the substance?
a. A
b. B
c. C
d. D
e. E
8. A solution prepared by dissolving 0,60 grams of nicotine (a non electrolyte) in water to make a 12 mL of solution has an osmotic pressure of 7,55 atm at 250C. Mr of nicotine is …. (R = 0,082 L atm/K mol)
a. 120
b. 160
c. 200
d. 140
e. 280
9. Which of the following solutes will produce the highest solution boiling point when dissolved in water?
a. 2 moles of NaCl
b. 1 mole of ethanol
c. 1 mole of MgCl2
d. 2 moles of methanol
e. 1 mole of methanol
10. Balance the following equation in alkaline solution and determine the coefficient of OH- and its location (right or left side) in the equation.
MnO4- + Ni --> Ni(OH)2 + MnO2
a. 5, left
b. 2, right
c. 4 ,right
d. 2, left
e. 4, left
11. How many electrons are transferred in the following reaction?
CH4(g) + 2O2(g) --> CO2(g) + 2H2O(l)
a. 1
b. 2
c. 3
d. 6
e. 8
12. Given the balanced reaction:
2Al(s)+6H+(aq) --> 2Al3+(aq) +3H2(aq)
What is the total number of moles of electrons gained by H+(aq) when 2 moles of Al(s) is completely reacted?
a. 12
b. 10
c. 6
d. 3
e. 2
13. After balancing the redox reactions below, the value of a, b, c, d, and e in order are ….
aNa2C2O4 + bK2Cr2O7 + cH2SO4 --> dCO2 + Cr2(SO4)3 + K2SO4 + Na2SO4 + eH2O
a. 3, 1, 7, 3, 7
b. 3, 1, 7, 6, 7
c. 3, 2, 7, 3, 7
d. 6, 2, 7, 6, 7
e. 6, 1, 7, 3, 7
14. The diagram below represents an electrochemical cell of Zn – Cu.

What occurs when the switch is on?
a. Zn is reduced.
b. Cu is oxidized
c. Electrons flow from Cu to Zn.
d. Electrons flow from Zn to Cu.
e. Electric current flows from Zn to Cu
15. In an electrochemical cell, what is the purpose of the salt bridge?
a. It is the anode.
b. It is the cathode.
c. It permits the migration of ions between the half-cells.
d. It permits the mixing of solutions between the half-cells.
e. It permits the electrons flow
16. Based on the cell notation for a spontaneous reaction, at the anode ….
Zn(s) + Zn2+(aq) --> Fe3+(aq) + Fe2+ (C)
a. Zn becomes oxidized
b. Fe3+ becomes reduced
c. Fe2+ becomes oxidized
d. Zn2+ becomes reduced
e. H2O becomes oxidized
17. From the following listed standard electrode potentials, the biggest Eo for the cell is ….
Mg2+(aq) + 2e --> Mg(s) Eo = --2,24 V
Sn2+(aq) + 2e --> Sn(s) Eo = --0,14 V
Hg2+(aq) + 2e --> Hg(s) Eo = +0,62 V
Cu2+(aq) + 2e --> Cu(s) Eo = +0,34 V
a. Mg(s)/Mg2+ (aq)//Cu2+(aq)/Cu(s)
b. Mg(s)/Mg2+(aq)//Hg2+(aq)/Hg(s)
c. Sn(s)/Sn2+ (aq)//Hg2+(aq)/Hg(s)
d. Sn(s)/Sn2+ (aq)//Cu2+(aq)/Cu(s)
e. Hg(s)/Hg2+ (aq)//Cu2+(aq)/Cu(s)
18. A metal, X can react with a solution of Y. Another metal, Z reacts with a solution of Y. However, Z cannot react with solution of X. The order of metal according to the decreasing reduction potentials is ….
a. X – Y – Z
b. Y – X – Z
c. Z – Y – X
d. Y – Z – X
e. X – Z – Y
19. From the listed standard electrode potentials, Eo for the cell is ….
(C) S2O32- :SO32- O2 OH- (C)
2 SO32-(aq) + 3 H2O(l) + 4 e- S2O32-+6OH- Eo = --0.580 VO2(g) + 2 H2O(l) + 4 e- 4 OH-(aq) Eo = +0.401 V
a. --0.98
b. --0.18
c. +0.18
d. +0.98
e. +49
20. Given the nickel-cadmium battery reaction:
2NiOOH+ Cd+ 2H2O --> 2 Ni(OH)2 + Cd(OH)2
What occurs during discharge in the nickel-cadmium battery?
a. Ni3+ is reduced to Ni2+.
b. Ni2+ is reduced to Ni3+.
c. Ni3+ is oxidized to Ni2+.
d. Ni2+ is oxidized to Ni3+
e. Water becomes OH- ions
21. CuSO4(aq) is electrolysed. Reaction which is occured at the positive electrode is ….
a. Cu(s) ® Cu2+(aq) + 2e
b. 2H+(aq) + 2e ® H2(g)
c. 2H2O(l) ® 4H+(aq) + 4e + O2(g)
d. Cu2+(aq) + 2e ® Cu(s)
e. 2SO42-(aq) + 2H2O(l) ®2H2SO4 + 4e + O2(g)
22. Which metal is used as a coating on steel to limit corrosion?
a. Na
b. Ca
c. K
d. Zn
e. Fe
23. How many minutes will it take to plate out 5.00 g of Cr from a Cr2(SO4)3 solution using a current of 1.50 A? (Ar: Cr = 52)
a. 309
b. 254
c. 205
d. 152
e. 103
24. Sodium metal is produced commercially by the electrolysis of molten sodium chloride and chlorine is produced as a by product. How many liters of chlorine at 10 atm and 20oC will be produced if a current of 1.00 x 103 A is passed through NaCl (l) for 8.0 hours? (Ar: Cl = 35.5)
a. 4.6 x 102
b. 3.6 x 103
c. 3.6 x 102
d. 1.8 x 103
e. 1.8 x 102
25. The same electric current is flowed through CuCl2 (aq) and CrCl3 (aq) (Cu = 63,5 ; Cr = 52). If 0,635 grams of Cu is precipitated, the mass of Cr(s) is ….
a. 0,17 grams
b. 0,35 grams
c. 0,42 grams
d. 1,12 grams
e. 2,00 grams