How would you balance this equation: ?H_3PO_4 + ?Mg(OH)_2 -> ? Mg_3(PO_4)_2 + ? H_2O?

1 Answer
Nov 1, 2016

2 H_3PO_4 + 3 Mg(OH)_2 -> Mg_3(PO_4)_2 + 6 H_2O

Explanation:

To do it, I took the following steps :

  • Balance Mg:

I have 3 Mg in Mg_3(PO_4)_2 so I added 3 on the other side 3 Mg(OH)_2

  • Balance P :

Again I have 2 P in Mg_3(PO_4)_2 so I added 2 on the other side 2 H_3PO_4

  • Balance H :

I have 6 H in 2 H_3PO_4 (2xx3) and 6 H in 3 Mg(OH)_2 a total of 12 H so I added 6 next to H_2O
6 H_2O

Notice that the O is automatically balanced : 8 O in 2 H_3PO_4 + 6 O in 3 Mg(OH)_2 = 8 O in Mg_3(PO_4)_2 + 6 O in 6 H_2O

I hope that was clear