# How do you balance this reaction: ?Na_3PO_4(aq) + ?CaCl_2(aq) -> ?NaCl(aq) + ?Ca_3(PO_4)_2(s)?

Jan 2, 2017

As always, we must balance mass and charge............

#### Explanation:

$2 N {a}_{3} P {O}_{4} \left(a q\right) + 3 C a C {l}_{2} \left(a q\right) \rightarrow 6 N a C l \left(a q\right) + C {a}_{3} {\left(P {O}_{4}\right)}_{2} \left(s\right) \downarrow$

Are charge and mass balanced here?

As a matter of fact, this is a simplified version of what occurs in solution. Phosphates in water are commonly the $\text{biphosphate ion}$, $H P {O}_{4}^{2 -}$.

The reaction is probably better represented as:

$N {a}_{2} H P {O}_{4} \left(a q\right) + C a C {l}_{2} \left(a q\right) \rightarrow 2 N a C l \left(a q\right) + C a \left(H P {O}_{4}\right) \left(s\right) \downarrow$

But you have to go with what your teacher says, not what I say.