when the unbalanced reaction equation is:
Ca(NO3)2 + H3PO4 → Ca3(PO4)2 + HNO3
this is not balanced equation as the numbers of all the atoms are not equal on both sides of the equation.
we have 1 C atom of the left side and 3 atoms on the right side.
we have 2 of NO3 group on the left side and 1 of NO3 group on the right side
and we have 3 H atoms on the left side and 1 atom on the right side.
and there is 1 of PO4 group on the left side and 2 of PO4 group on the right side.
so we have to balance the equation first:
we put 3 Ca(NO3)2 instead of Ca(NO3)2 to make C atoms equal on both sides.
and we put 6HNO3 instead of HNO3 to make NO3 group equals on both sides.
and we put 2 H3PO4 instead of H3PO4
so the final balanced equation will be:
3Ca(NO3)2 + 2H3PO4 → Ca3(PO4)2 + 6HNO3
∴ the coefficients in front of H3PO4 will be 2
