Answer:
a.
![Ca(NO_3)_2(s)\rightarrow Ca^(2+)+2NO_3^-](https://img.qammunity.org/2021/formulas/chemistry/college/7228yya6dhydbder7vlciv15d68q8bgxfm.png)
b.
![Na_3PO_4(s)\rightarrow 3Na^(+)+PO_4^(-3)](https://img.qammunity.org/2021/formulas/chemistry/college/si6etjvnylnerchkt8tngd7eimq8srwzsl.png)
Step-by-step explanation:
Hello,
In this case, considering that the dissolution reaction of a solid in aqueous solutions involve the dissociation (separation) of both its cation and anion for the required salts we write:
a.
![Ca(NO_3)_2(s)\rightarrow Ca^(2+)+2NO_3^-](https://img.qammunity.org/2021/formulas/chemistry/college/7228yya6dhydbder7vlciv15d68q8bgxfm.png)
b.
![Na_3PO_4(s)\rightarrow 3Na^(+)+PO_4^(-3)](https://img.qammunity.org/2021/formulas/chemistry/college/si6etjvnylnerchkt8tngd7eimq8srwzsl.png)
Thus, a two is required for nitrate anions in a. in order to balance it at the reactant and a three is required for sodium cations in b. in order to balance it as well.
Best regards.