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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: JeanPaulSB on March 15, 2021, 12:50:54 AM

Title: Problem while balancing an Equation by Redox Method (Ill possed problem?)
Post by: JeanPaulSB on March 15, 2021, 12:50:54 AM

Hi guys, i have a problem while balancing this equation idk if it is an ill possed problem,  i tried to solve it too many times and i can't get an answer, this equation was assigned by my teacher and need to be solved by redox method.

PH3 + KMnO4 + H2SO4 → K2SO4 + MnSO4 + H3PO4

Trying to solve it, i got this

5PH3+8KMnO4+H2SO4→ K2SO4+8KMnO4+5H3PO4.

I felt so confused with this, pls help me guys :(

Title: Re: Problem while balancing an Equation by Redox Method (Ill possed problem?)
Post by: chenbeier on March 15, 2021, 02:58:51 AM

Start with redox pair

PH₃ to H₃PO₄
MnO₄^- to Mn²⁺

PH₃ + 4 H₂O => H₃PO₄ + 8 H+ + 8 e-

MnO₄^- + 8 H⁺ + 5 e^- => Mn²⁺ + 4 H₂O

Can you work further

Title: Re: Problem while balancing an Equation by Redox Method (Ill possed problem?)
Post by: Borek on March 15, 2021, 04:14:49 AM

Quote from: JeanPaulSB on March 15, 2021, 12:50:54 AM

PH3 + KMnO4 + H2SO4 → K2SO4 + MnSO4 + H3PO4

This equation can't be balanced as written, you need one more product.