Which of the following aqueous solution has highest pH

To determine which of the following aqueous solutions has the highest pH, we need to compare the concentration of hydroxide ions (OH-) in each solution. The higher the concentration of hydroxide ions, the higher the pH.

First, let's list the options for the aqueous solutions:

1. Sodium hydroxide (NaOH)
2. Hydrochloric acid (HCl)
3. Ammonium hydroxide (NH4OH)
4. Acetic acid (CH3COOH)

To determine the pH, we need to consider the dissociation of each compound in water.

1. Sodium hydroxide (NaOH) dissociates completely in water to form Na+ and OH- ions. Since it is a strong base, it will have a high concentration of hydroxide ions, resulting in a high pH.

2. Hydrochloric acid (HCl) dissociates completely in water to form H+ and Cl- ions. Since it is a strong acid, it will have a low concentration of hydroxide ions, resulting in a low pH.

3. Ammonium hydroxide (NH4OH) partially dissociates in water to form NH4+ and OH- ions. It is a weak base, so it will have a lower concentration of hydroxide ions compared to sodium hydroxide.

4. Acetic acid (CH3COOH) partially dissociates in water to form CH3COO- and H+ ions. It is a weak acid, so it will have a very low concentration of hydroxide ions.

Based on this information, we can conclude that sodium hydroxide (NaOH) will have the highest pH among the given options.