Arrange the following 0.100 mol L-1 solutions in order of increasing pH:
CH3COOH, NaCl, NaCH3Coo
To arrange the solutions in order of increasing pH, we need to first understand the properties of each solution.
pH is a measure of the acidity or basicity of a solution, with lower pH values indicating higher acidity and higher pH values indicating higher basicity.
Let's analyze each solution:
1. CH3COOH (acetic acid): This is a weak acid. When it dissolves in water, it partially dissociates into H+ ions and CH3COO- ions. Since it is a weak acid, only a small fraction of CH3COOH donates H+ ions, resulting in a relatively low concentration of H+ ions in solution. Therefore, the pH of this solution will be relatively higher compared to a strong acid.
2. NaCl (sodium chloride): This is a neutral salt. It is formed by the reaction between a strong acid (HCl) and a strong base (NaOH), resulting in the formation of Na+ and Cl- ions. Since neither of these ions reacts with water to produce H+ or OH- ions, the solution remains neutral. Therefore, the pH of the NaCl solution will be neutral, which is 7.
3. NaCH3COO (sodium acetate): This is formed by the reaction between a weak acid (acetic acid) and a strong base (NaOH). In this case, the weak acid is partially ionized and donates CH3COO- ions when dissolved in water. These CH3COO- ions can react with water to form a small amount of OH- ions, making the solution slightly basic. Therefore, the pH of this solution will be higher compared to the acetic acid solution but lower than 7.
Based on this analysis, the solutions can be arranged in increasing pH order as follows:
1. CH3COOH (acetic acid)
2. NaCH3COO (sodium acetate)
3. NaCl (sodium chloride)