Question

4) Small amounts of chlorine gas can be produced from the electrolysis of aqueous solutions of sodium chloride (NaCl). In a particular experiment, electrolysis of an aqueous solution of sodium chloride is carried out for 2.00 hours using a current i = 3.00 amps (1 amp = 1 C/s). How many grams of Cl2 gas are produced? (HINT: What is the half-reaction for forming Cl2(g) from Cl- ions?)

Answer 1

BY Faraday's First law of electrolysis ,

Mass of a substance deposited or liberated is directly proportional to quantity of current used for electrolysis.

m = e* c* t

c= 3 amps of current

time = 2 hrs

= 2* 3600 s

m= mass of the substance deposited or liberated at the electrode.

c= current in amp.

t = time in seconds.

e= electrochemical equivalent.

OR

By definition , electrochemcial equivalent is the mass of the susstance deposited or liberated when 1 coloumb of current is used ( 1C = 1 amp * 1 sec)

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At Anode -------- Oxidation

Since it is quantity of chlorine gas to be calculated ,electrochemcial equivalent ,e of chlorine gas =

  

= 0.0003678 g/C

mass of chlorine gas liberated at anode

m = e* c* t

= 0.0003678 g/C * 3 amps * 2 * 3600 s

= 7.946 g of Chlorine gas is prodcued at anode.