Page 1 of 1

Desperate need of help with redox half cell reaction

Posted: Fri May 08, 2020 10:25 am
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.

Posted: Fri May 08, 2020 11:02 am
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

finished.

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

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