Which description best fits a solution that conducts electricity and turns red litmus blue?

Which description best fits a solution that conducts electricity and turns red litmus blue?

• A. A weak base
• B. A strong base
• C. A strong acid
• D. A weak acid

Answer: (B)

Turning red litmus blue shows the solution is basic, because bases make the solution alkaline enough to convert red to blue. The fact that it conducts electricity means there are mobile ions present. A strong base fully dissociates in water, producing a high concentration of hydroxide ions and other ions, which gives both the blue litmus result and strong ionic conductivity. A weak base would also turn red litmus blue, but its ionization is incomplete, so it would produce fewer ions and weaker conductivity. A strong acid would turn red litmus blue? actually it would turn it red, not blue, so it doesn’t match the observation. Therefore, the description that best fits is a strong base.

Turning red litmus blue shows the solution is basic, because bases make the solution alkaline enough to convert red to blue. The fact that it conducts electricity means there are mobile ions present. A strong base fully dissociates in water, producing a high concentration of hydroxide ions and other ions, which gives both the blue litmus result and strong ionic conductivity. A weak base would also turn red litmus blue, but its ionization is incomplete, so it would produce fewer ions and weaker conductivity. A strong acid would turn red litmus blue? actually it would turn it red, not blue, so it doesn’t match the observation. Therefore, the description that best fits is a strong base.