Answer:
(a) H₃O⁺(aq) + H₂PO₄⁻(aq) ⟶ H₃PO₄(aq) + H₂O(ℓ)
(b) OH⁻(aq) + H₃O⁺(aq) ⟶ 2H₂O(ℓ)
Explanation:
The equation for your buffer equilibrium is:
H₃PO₄(aq) + H₂O(ℓ) ⇌ H₃O⁺(aq)+ H₂PO₄⁻(aq)
(a) Adding H₃O⁺
The hydronium ions react with the basic dihydrogen phosphate ions.
H₃O⁺(aq) + H₂PO₄⁻(aq) ⟶ H₃PO₄(aq) + H₂O(ℓ)
(b) Adding OH⁻
The OH⁻ ions react with the more acidic hydronium ions.
OH⁻(aq) + H₃O⁺(aq) ⟶ 2H₂O(ℓ)

Thus 174 protons would make at most 6 copper atoms. However, it would take 174 extra electrons (29 per atom) and even more neutrons than that to construct neutral copper atoms with stable nuclei.
Cell division is the process by which a parent cell divides into two or more daughter cells. Cell division usually occurs as part of a larger cell cycle