Desperate need of help with redox half cell reaction

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Desperate need of help with redox half cell reaction

Post by pavs323 »

It’s Pa(OH)3+ / Pa2O5

After evaluating valence, I always get
Pa=4 for Pa(OH)3+
Pa=5 for Pa2O5

Then the formula of

Pa2O5+ (H+)+ (e-)=(Pa(OH)3+)+ H2O

I don’t know what I’m doing wrong but even if I neglect the rules and put Pa(OH)3 on the left, I cannot balance this thing. No matter what I do, once I balance Pa either the oxygens or hydrogens are not even, and then if I balance those it screws up the protactitinum. I must have re started and tried this one probably 20 times and have no idea what to do. Any help is much appreciated, but I’d prefer explanations rather than solely the answer as I do want to know what I’m doing wrong.
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Post by ChenBeier »

Pa(OH)3+/ Pa2O5

2 Pa(OH)3+/Pa2O5 times 2

2 Pa(OH)3+ => Pa2O5 + H2O + 4 H+ balance with H+ and water

2 Pa(OH)3+ => Pa2O5 + H2O + 4 H+ 2 e- balance charge


But I would formulate it with Hydroxide, because Hydroxide complex is used.

2 Pa(OH)3+ + 4 OH- => Pa2O5 + 5 H2O + 2 e-
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