Answer: The number of moles of sodium phosphate required is 0.33 moles
Step-by-step explanation:
We are given:
Moles of silver nitrate = 1 mole
The chemical equation for the reaction of sodium phosphate and silver nitrate follows:

By Stoichiometry of the reaction:
3 moles of silver nitrate reacts with 1 mole of sodium phosphate.
So, 1.0 moles of silver nitrate will react with =
of sodium phosphate.
Hence, the number of moles of sodium phosphate required is 0.33 moles