Final answer:
The correct statement describing the hydronium-hydroxide balance in a given solution is that in bases, the concentration of hydroxide ions ([OH-]) is greater than the concentration of hydronium ions ([H3O+]). Neutral solutions have equal concentrations of [H3O+] and [OH-], each being 1 × 10-7 M at 25 °C.
Step-by-step explanation:
The correct statement that describes the hydronium-hydroxide balance in a given solution is D. In bases, [OH-] is greater than [H3O+]. For the other options: A is incorrect because in acids, the hydronium concentration ([H3O+]) is greater than the hydroxide concentration ([OH-]).
B is incorrect because in bases, [OH-] is greater than [H3O+], not equal. C is incorrect because [H3O+] is equal to [OH-] in neutral solutions, not [H2O]. E is incorrect since it states the opposite of the correct relationship in bases.
A neutral solution is when [H3O+] = [OH-] and both are 1 × 10-7 M at 25 °C. In acidic solutions, [H3O+] is greater than 1 × 10-7 M and in basic solutions, [OH-] is greater than 1 × 10-7 M, making [H3O+] less than 1 × 10-7 M.