Ba(oh)2+H3po4+h2o how is it
balance ?

3Ba(OH)2 + 2H3PO4 —> Ba3(PO4)2 + 6H2O

Explanation:

Ba(OH)2 + H3PO4 —> Ba3(PO4)2 + H2O

There are 3 atoms of Ba on the right side and 1atom on the left side. It can be balance by putting 3 in front of Ba(OH)2 as shown below:

3Ba(OH)2 + H3PO4 —> Ba3(PO4)2 + H2O

There are 2 atoms of P on the right side and 1atom on the left. It can be balance by putting 2 in front of H3PO4 as shown below:

3Ba(OH)2 + 2H3PO4 —> Ba3(PO4)2 + H2O

Now, there are a total of 12 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 6 in front of H2O as shown below:

3Ba(OH)2 + 2H3PO4 —> Ba3(PO4)2 + 6H2O

Now the equation is balanced as the numbers of the atoms of the different elements present on both sides are equal

there are two significant figures.