Which statement correctly describes a basic solution?

Which statement correctly describes a basic solution?

• A. Conductor of electricity
• B. Causes an indicator color change
• C. Has a greater [H3O+]
• D. Has a greater [OH-]

Answer: (D)

In a solution, acids raise the hydronium ion concentration while bases raise the hydroxide ion concentration. A basic solution is one where the concentration of hydroxide ions is greater than that of hydronium ions, which also means the pH is greater than 7 and the pOH is less than 7. The statement that describes a basic solution is that it has a greater [OH−] than [H3O+]. This comes from the equilibrium for water, [H3O+][OH−] = 1.0 × 10^−14 at room temperature, so increasing OH− automatically lowers H3O+ and shifts the solution toward basicity. The other ideas—conductivity, indicator color changes, or having more H3O+—aren’t unique to bases and can occur in many solutions, while having more OH− directly defines basicity.

In a solution, acids raise the hydronium ion concentration while bases raise the hydroxide ion concentration. A basic solution is one where the concentration of hydroxide ions is greater than that of hydronium ions, which also means the pH is greater than 7 and the pOH is less than 7. The statement that describes a basic solution is that it has a greater [OH−] than [H3O+]. This comes from the equilibrium for water, [H3O+][OH−] = 1.0 × 10^−14 at room temperature, so increasing OH− automatically lowers H3O+ and shifts the solution toward basicity. The other ideas—conductivity, indicator color changes, or having more H3O+—aren’t unique to bases and can occur in many solutions, while having more OH− directly defines basicity.