Question

3-26) Pb2+ + H2C2O4Pb + 2CO2+ 2H+ In the above reaction, the oxidation state of carbon changes from___ to ___ (-7<x<+7)

How many electrons are transferred in the reaction? ____

Answer 1

In the reaction,

Pb²⁺ + H₂C₂O₄ -----> Pb + CO₂ + 2H⁺

the oxidation state of carbon in H₂C₂O₄ (oxalic acid) is +3

total charge of oxygen = -2*4 = -8

total charge of Hydrogen = 2

net charge on oxalic acid = 0

so -8+2 +(2*x) = 0

x = 3

Now oxidation state of carbon in CO2 = 4

change in oxidation state is 3-4 = -1

so, the oxidation state of carbon changes from 3 to 4.

There are two electrons transferred in the reaction because the oxidation state of Pb changes from 2+ to 0.