Sodium hyroxide is NaOH.
Phosphoric acid is H3PO4.
So NaOH and H3PO4 react in different proportions to produce Na3PO4 (if all 3 H atoms are replaced)[leaving no H], Na2HPO4 (if only 2 H atoms are replaced)[leaving 1 H], or NaH2PO4 (if only 1 H atom is replaced)[leaving 2 H]. The PO4 ion is -3 and Na is +1. All you are doing is replacing a +1 H with +1 Na (or two or three as the case may be). I hope this helps but repost if it doesn't and explain in detail what you don't understand.
I don't understand the formula for sodium hydrogen phosphate. Can you please tell me it and explain it?
4 answers
so how do i know which one is correct? If i understand correctly you said it could be Na2HPO4 or NaH2PO4...
also i don't understand how there can be +1 Na and then a -3 PO4...
wouldn't it then have to be Na3 to balance?
sorry i'm really lost
also i don't understand how there can be +1 Na and then a -3 PO4...
wouldn't it then have to be Na3 to balance?
sorry i'm really lost
The names let one sort out which.
Name One
Sodium hydrogen phosphate
sodium monohydrogen phosphate
disodium hydrogen phosphate
Name two:
sodium dihydrogen phosphate
monosodium hydrogen phosphate
monosodium dihydrogen phosphate
I have seen all names used.
On your last question, remember than H has a charge of +1.
Name One
Sodium hydrogen phosphate
sodium monohydrogen phosphate
disodium hydrogen phosphate
Name two:
sodium dihydrogen phosphate
monosodium hydrogen phosphate
monosodium dihydrogen phosphate
I have seen all names used.
On your last question, remember than H has a charge of +1.
There is one sodium phosphate, Na3PO4, and 2 sodium hydrogen phosphates (one is sodium dihydrogen phosphate [NaH2PO4] which is also called monosodium dihydrogen phosphate and one is disodium hydrogen phosphate [Na2HPO4] which may also be called disodium monohydrogen phosphate.
Yes, IF all three hydrogen atoms are replaced on H3PO4, the acid, then Na3PO4 is what is formed because, as you correctly point out, PO4 is -3 and Na is +1. But when H3PO4, containing three replaceable H atoms reacts with a monoprotic base, such as NaOH, it CAN replace all three, or only 2, or only 1.
The charges, obviously, are PO4^-3, H2PO4^-1, and HPO4^-2. You can see that if we add 1 H ion to PO4^-3 we have left HPO4^-2 because -3 and +1 = -2 or if we add 2 H ions to PO4^-3, we have left H2PO4^- because -3 and +(2x+1) = -3 + 2= -1. I hope this is better.
Yes, IF all three hydrogen atoms are replaced on H3PO4, the acid, then Na3PO4 is what is formed because, as you correctly point out, PO4 is -3 and Na is +1. But when H3PO4, containing three replaceable H atoms reacts with a monoprotic base, such as NaOH, it CAN replace all three, or only 2, or only 1.
The charges, obviously, are PO4^-3, H2PO4^-1, and HPO4^-2. You can see that if we add 1 H ion to PO4^-3 we have left HPO4^-2 because -3 and +1 = -2 or if we add 2 H ions to PO4^-3, we have left H2PO4^- because -3 and +(2x+1) = -3 + 2= -1. I hope this is better.