Acids Bases And Salts

Step 1: The pH of an acid solution is determined by the hydrogen ion concentration: Adding a more concentrated solution of HCl increases the hydrogen ion concentration, lowering the pH.
Step 2: Comparing given solutions: - Increasing the molarity from 0.01 M to 0.02 M results in an increase in , leading to a lower pH. - Other options either dilute the solution or keep the concentration unchanged, making option (1) correct.