Explanation:
Chemical equilibrium is the reaction state where the rate of reactants reacting is equal to rate of products deteriorating.
1. Adding benzoate ions to the mentioned equation will shift the equilibrium towards reactant side making more benzoic acid.
2. Adding NaOH to remove hydrogen ions will make the benzoic acid ionize more and hence shift the equilibrium towards products.
3. Adding benzoic acid more will shift the equilibrium towards products.
4. Increasing the hydrogen ion concentration will shift the equilibrium towards reactant, thereby crystalizing the benzoic acid.
5. Cooling the solution will also shift the equilibrium towards reactant side making effective crystals.