Question 28

A basic solution

Adding a basic solution is the most effective way to neutralize a solution with a pH of 5, as it will raise the pH toward neutrality (pH 7) by neutralizing the excess hydrogen ions present in the solution.

A) Pure water

While adding pure water can dilute the solution and slightly raise the pH, it does not actively neutralize the acidity. Therefore, it is not an effective method for achieving the desired neutralization.

B) An acidic solution

Adding another acidic solution would further lower the pH of the solution, making it more acidic rather than neutral. This option is counterproductive to the goal of neutralization.

C) A basic solution

A basic solution effectively neutralizes the acidic solution by providing hydroxide ions that react with hydrogen ions, resulting in water and increasing the solution's pH toward neutral. This is the correct method for neutralization.

D) A sodium chloride solution

Sodium chloride, or table salt, does not alter the pH of a solution significantly. It would neither neutralize the acidity nor create a basic environment, making it ineffective for this purpose.

Conclusion

The best method to neutralize a solution with a pH of 5 is to add a basic solution, as it directly counteracts the acidity. Other options, such as water, acidic solutions, and sodium chloride, do not provide the necessary chemical reaction to effectively increase the pH and achieve neutrality.