When tested, a solution turns red litmus to blue. This indicates that the solution contains more

When tested, a solution turns red litmus to blue. This indicates that the solution contains more

• A. H+ ions than OH- ions
• B. H3O+ ions than OH- ions
• C. H+ and OH- ions than H2O molecules
• D. OH- ions than H3O+ ions

Answer: (D)

A basic solution turns red litmus blue because it has more hydroxide ions than hydronium ions. When OH− outnumbers H3O+, the pH is above 7, so the red litmus changes to blue. If there were more H3O+ (more acidic conditions), the solution would not turn blue. The idea that both H+ and OH− outnumber water molecules doesn’t relate to the indicator’s color in the same way. Therefore, having a greater amount of OH− than H3O+ explains why the red litmus becomes blue.

A basic solution turns red litmus blue because it has more hydroxide ions than hydronium ions. When OH− outnumbers H3O+, the pH is above 7, so the red litmus changes to blue. If there were more H3O+ (more acidic conditions), the solution would not turn blue. The idea that both H+ and OH− outnumber water molecules doesn’t relate to the indicator’s color in the same way. Therefore, having a greater amount of OH− than H3O+ explains why the red litmus becomes blue.