Measuring of pH values of Unknown Solutions

2020-05-28

Measuring of pH values of Unknown Solutions

4 beakers labeled A, B, C, and D contain 0.1 M solutions of the following salts: NaHCO₃, NH₄Cl, CH₃COONa, and FeCl₃. Identify which solution is in each beaker by measuring the pH and observing their reactions with either NaOH or HCl.

pH Measurement: The pH of each unknown solution was measured using a pH meter. The sensor was immersed in each solution, and the pH value was recorded once it had stabilized. This provided an initial indication of the acidity or basicity of the solutions.

Chemical Testing: A few drops of 0.5 M NaOH or 0.5 M HCl were added to the solutions if necessary to further clarify the identity of the salts. Changes in pH or observable reactions were noted.

NaHCO₃ (Sodium bicarbonate): A weak base with a slightly basic pH

NH₄Cl (Ammonium chloride): A salt of a weak base (NH₃) and a strong acid (HCl), expected to have an acidic pH

CH₃COONa (Sodium acetate): A salt of a weak acid (CH₃COOH) and a strong base (NaOH), expected to have a basic pH

FeCl₃ (Iron(III) chloride): Undergoes hydrolysis to form acidic Fe³⁺ ions, resulting in a strongly acidic pH

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