Chemical Forums

Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: qwerty on February 20, 2011, 08:02:21 PM

Title: Chemistry redox reactions?
Post by: qwerty on February 20, 2011, 08:02:21 PM

Can someone help me with redox reactions . It is urgent.

Are these half-reactions correct :
It is from this equation
Mn2+ + NaBiO3 + H+ -----> MnO2 + Bi3+ + Na+ + H2O


Mn2+ ---> MnO2 + 2e-
NaBiO3 + 2e- ---> Bi3+


This is another equation :

Mn2+ + NaBiO3 + H+ -----> MnO4- + Bi3+ + H2O + Na+

I need the oxidation reduction equation for it . Please explain it to me as you do it. Don't just
answer it

This is another equation:

MnO4- + H2O2 + H+ ------> Mn2+ + O2

I don't understand which oxygen will be oxidized since there are two of them on the left
one is in MnO4 and one in H2O2...please give me an explanation

Thanks. I appreciate the help

Title: Re: Chemistry redox reactions?
Post by: Borek on February 21, 2011, 04:39:58 AM

Quote from: qwerty on February 20, 2011, 08:02:21 PM

Mn2+ ---> MnO2 + 2e-
NaBiO3 + 2e- ---> Bi3+

Half reaction needs to be balanced in terms of atoms & charge, these are not.

Quote

MnO4- + H2O2 + H+ ------> Mn2+ + O2

I don't understand which oxygen will be oxidized since there are two of them on the left
one is in MnO4 and one in H2O2.

You don't have a complete list of products. To see which oxygen will be oxidized start assigning oxidation numbers.