Question

In the electrolysis of a sodium chloride solution, what vol- ume of Cl2(g) is produced in the same time it takes to produce 6.00 L of H2(g), both volumes measured at 0 C and 1.00 atm?

How do we know which one is oxidized or reduces in favor of the other one?

Answer 1

Electrolysis reaction can be represented as

2NaCl+H2O---->2 NaOH+ H2+Cl2

1 mole of Cl2 and 1 mole of H2 produced duriing electrolysis. Since temperature and pressure remain constant.

where n1 = mole of Hydrogen gas which are same as that of chlorine = PV/RT=1*6/(0.08206*273.15)=0.27 moles

moles of Cl2 produced=0.27 moles

Volume of Cl2 produced = nRT/P= 0.27*0.08206*273.15/1=6 L

At anode the following reaction takes place

Reduction 2H+2e----> H2(g)

Oxidation 4OH----> 2H2O+O2+4e-