Question

I'm struggling to balance a redox reaction

Answer 1

\[Cr_2 O_7^{2-} + PH_3 \rightarrow Cr ^{3+} + P_2 O_5 \]

Answer 2

Balancing...What happened to your H3?

Answer 3

not sure what you're asking

Answer 4

Is PH3 a part of your equation? Or is it just P?

Answer 5

According to the equation you have..

Answer 6

I think I see what you're trying to say, there isn't an H on the product side, I'm wondering if I copied the problem down wrong from the beginning. Thanks for trying to help me

Answer 7

You're welcome :) Just curious to what that was..

Answer 8

Assign oxidation numbers. Identify what is being oxidized and reduced. In this example chromium is being reduced from a +6 oxidation state to a +3 state.

Determine the simplest whole number of electrons that balances electron transfer. That is how to get the coefficients for the redox entities.

If necessary, add water to one side to balance oxygen.

This will add hydrogen, so balance the hydrogen by adding hydrogen ions. If the reaction takes place in basic solution, add hydroxide. You may then be able to combine some hydroxide and hydrogen ions to make water. Finally, cancel out any excess water.

Mass and charge should be in balance.

You could also begin by writing half reactions. Once the redox coefficients have been determined, you can continue as with the steps listed above.