[Type here]
ELECTROCHEMISTRY – 1 (FARADAY’S LAW)
1. 2.5 ampere of current is pass through CuSO4 solution for 30 minutes. Calculate the weight of copper in
the cathode. Find the number of copper atoms.
2. 0.268 ampere current is passed through a solution of a metallic ion for 30 minutes. When 0.266 g of the
metal is deposited. The specific heat of the metal 0.0565. Find the oxidation number of the metallic ion
and the atomic weight of the metal.
3. By passing 0.25 ampere current through CuSO4 solution for 1 hour, 0.295 g of copper is deposited. Find
the equivalent weight of copper. (F = 96500 coulomb)
4. 0.5 ampere current is passed through CuSO4 solution for 30 minutes when 0.2964 g of copper is
deposited at the cathode. Find the atomic weight of copper.
5. How long will take for a current of 4 amperes to liberate 10 g of Cu from a 1.2 molar solution of copper
sulphate? (Cu = 63)
6. 1.93 ampere of current is passed through dil. H2SO4 for 15 minutes. Calculate (i) weight of H2 (ii)
number of gram- mole of hydrogen, (iii) volume of hydrogen at N.T.P., (iv) number of hydrogen
molecules, (v) volume of electrolytic gases at N.T.P.
7. 2 ampere of current is passed through 100 ml of 0.5 (N) CuSO4 solution for some time. After electrolysis
the concentration of the resulting solution becomes 0.1 (N). Find the time of passing electric current.
8. A 100 watt, 110 volt incandescent lamp is connected in series with an electrolyte cell containing CdSO4
solution. What weight of cadmium will be deposited by the current flowing for 10 hours?
9. Determine the amount of electricity in coulomb required to deposit copper of thickness 10-3 cm on a
plate having area of 100 cm cm using copper sulphate solution. (Density of Cu = 8.94 g/cc, Cu = 63.5)
10. How many coulombs are required for the following reduction?
(i) 1 mole of Cu2+ to Cu (ii) 1 mole of Mno-4 to Mn2+
11. How many moles of electrons will be required to discharge (a) 1 mole of Ag+ (b) 1 mole of Cu2+?
12. Chromium metal can be plated out from an acidic solution containing CrO3 according to the following
equation:
CrO3 (aq) + 6H+ (aq) + 6e- →Cr(s) + 3H2O
(i) Calculate how many gram of Cr (atomic weight 52) will be plated out by passing 24000 coulombs of
electricity.
(ii) If a current of 24 amp is being used, how long will it take to plate out the amount of Cr calculated
in (i) above?
13. If the value of the faraday is 120460 coulombs, what will be the charge of an electron?
[Type here]
ANSWER KEY
1. 1.4815 gm, 1.404 X 1022 atoms 2. +2, 106.4 g 3. 31.63 4. 63.56
5. 2 hrs 7 mints 38 sec 6. 0.018 g, 0.009 gram-mole, 0.2016 litre, 5.42 X 1021 molecules
of hydrogen, 0.3024 lt.
7. 1930 seconds 8. 19.06 g 9. 2717.19 coulomb
10. 193000 coulombs, 482500 coulombs 11. 1 mole, 2 mole 12. 2.155 g, 1000 sec
13. 2.0009 x 10-19 C
