On adding of the following, the pH of 20 ml of 0.1 N HCl will not alter?A. 1 ml of 1N HClB. 20 ml of distilled waterC. 1 ml of 0.1N NaOHD. 500 ml of HCl of pH=1

To determine which addition will not alter the pH of the solution containing 20 ml of 0.1 N HCl, let's analyze each option:

A. Adding 1 ml of 1N HCl: This addition will increase the concentration of HCl in the solution, but since both the added HCl and the original HCl are strong acids, the pH will remain the same or very close to it.

B. Adding 20 ml of distilled water: Distilled water has a neutral pH of 7, adding it to the acidic solution will dilute the concentration of HCl, leading to a slight increase in pH, but since the amount added is equal to the initial volume, the change may be negligible.

C. Adding 1 ml of 0.1N NaOH: NaOH is a strong base. Mixing it with HCl will lead to neutralization, forming water and a salt. This reaction will reduce the concentration of HCl, leading to an increase in pH. Therefore, this addition will alter the pH.

D. Adding 500 ml of HCl with a pH of 1: This addition will significantly increase the concentration of HCl in the solution, leading to a decrease in pH, making the solution even more acidic.

So, the addition that will not alter the pH of the solution containing 20 ml of 0.1 N HCl is option A, adding 1 ml of 1N HCl.