Problems B
317
Compound
BaBr 2
AI 2 (S0 4 ) 3
SnCI 4
Cd(N0 3 ) 2
K 3 P0 4
Electrode
material
Ag
Pt
c
Cd
Zn
Negative electrode
Substance
produced
Amount
produced
Positive electrode
Substance
produced
Amount
produced
11. What weight of each of the following will be liberated by the passage of
0.650 faraday of electricity?
(a) Pt from PtCl 4
(b) O 2 from A1(NO 3 ) 3
(c) Ba from BaCl 2
(d) H 2 from H 3 PO 4
(e) Zn from ZnSO 4
12. How long will it take a current of 2.50 amp to deposit the silver from 650 ml of
a 0.200 M AgNO 3 solution?
13. What current will be needed to deposit 2.50 g Cu in 15.0 min?
14. Platinum electrodes are placed in 400 ml of a 0.350 M NiSO 4 solution. If a
current of 1.75 amp is passed for 3.00 hr, what will be the NiSO 4 concentration at the end of that time?
15. A current of 4.50 amp is passed between copper electrodes in a 1.85 M CuSO 4
solution. What will be the concentration of the CuSO 4 at the end of 5.00 hr?
16. Using a current of 3.50 amp, how long will it take to produce 25.0 liters of H 2
(measured over water at 730 torr and 18.0°C) by the electrolysis of an H 2 SO 4
solution?
17. How many ampere-hours of electricity will be needed to refine electrolytically
1 ton of Cu by removing it from an impure positive electrode and depositing it
in a pure form on the negative electrode?
18. During the discharge of a lead storage battery, the density of the sulfuric acid
falls from 1.277 g/ml to 1.155 g/ml. Calculate the number of ampere-hours the
battery must have been used. The overall reaction in the battery is
Pb + PbO 2 + 2H,SO 4
2PbSO 4 + 2H 2 O
The more dense sulfuric acid is 37.0% H 2 SO 4 by weight, and the less dense is
22.0% H 2 SO 4 by weight. The battery holds 4.00 liters of acid. Assume that the
volume remains unchanged during discharge.
317
Compound
BaBr 2
AI 2 (S0 4 ) 3
SnCI 4
Cd(N0 3 ) 2
K 3 P0 4
Electrode
material
Ag
Pt
c
Cd
Zn
Negative electrode
Substance
produced
Amount
produced
Positive electrode
Substance
produced
Amount
produced
11. What weight of each of the following will be liberated by the passage of
0.650 faraday of electricity?
(a) Pt from PtCl 4
(b) O 2 from A1(NO 3 ) 3
(c) Ba from BaCl 2
(d) H 2 from H 3 PO 4
(e) Zn from ZnSO 4
12. How long will it take a current of 2.50 amp to deposit the silver from 650 ml of
a 0.200 M AgNO 3 solution?
13. What current will be needed to deposit 2.50 g Cu in 15.0 min?
14. Platinum electrodes are placed in 400 ml of a 0.350 M NiSO 4 solution. If a
current of 1.75 amp is passed for 3.00 hr, what will be the NiSO 4 concentration at the end of that time?
15. A current of 4.50 amp is passed between copper electrodes in a 1.85 M CuSO 4
solution. What will be the concentration of the CuSO 4 at the end of 5.00 hr?
16. Using a current of 3.50 amp, how long will it take to produce 25.0 liters of H 2
(measured over water at 730 torr and 18.0°C) by the electrolysis of an H 2 SO 4
solution?
17. How many ampere-hours of electricity will be needed to refine electrolytically
1 ton of Cu by removing it from an impure positive electrode and depositing it
in a pure form on the negative electrode?
18. During the discharge of a lead storage battery, the density of the sulfuric acid
falls from 1.277 g/ml to 1.155 g/ml. Calculate the number of ampere-hours the
battery must have been used. The overall reaction in the battery is
Pb + PbO 2 + 2H,SO 4
2PbSO 4 + 2H 2 O
The more dense sulfuric acid is 37.0% H 2 SO 4 by weight, and the less dense is
22.0% H 2 SO 4 by weight. The battery holds 4.00 liters of acid. Assume that the
volume remains unchanged during discharge.