Electrolysis Calculations

Question

  1. Assume that you are a Chemist in a chemical plant that deals with the production of chlorine gas. You want to produce 100 litres of chlorine gas per hour so that you can reach the Company's goal of producing 2400 litres every day. What current of electricity will you allow to flow per hour? (NECTA, 2014)

    2. Suggested Answers

    Method 1:

    2Cl- → Cl2 + 2e-
    From this equation:
    193000C → 22.4dm3
    ? C → 100dm3
    Q = 193000C X 100dm3
	22.4dm3
	= 861607C

    From

    Q = I.t
    where
    I = current
    t = time
    I = Q 
    t
    Therefore:
     
I = 861607C 
    3600s
    = 239.34A

    Method 2:

    From Faraday's first law of electrolysis 
    m = Ar.I.t
    v.F
    I = m.v.F
    Ar.t
    but
     mass = volume of a gas x molar mass
                  molar volume
     =100dm3 x 71g/mol
	22.4dm3
mass = 316.964g	
    I = 316.964g x 1 x 96500C
     35.5 x 3600s
    I= 239.34A

    The current 239.34A should be allowed to meet this demand.

    Ref: electrolysis