Question

pH of Buffered solutions: Acids, If the calculations do not fit into the table, then number the calculation and use a separate pH Calculations t n Sey Ayat Buffer 2 4.74 on Buffer 1A and но t . 52|1513 |0431시 A2 6 Se pava Da pv 119 Chem 24B pH of salts and buffers Revised Sp 17 Solution pH Buffer 2A and HCI 119 ow Buffer 1B and on Se vavante Buffer 2B and NaOH 5-3千 ơn pu Pev 2 re the calculatod pH of Buffer 1 to the calculated pH of Buffer 2. Do the two buffers have the same pH even though the two buffers have a different concentration? Explain why the pH of the two buffer solutions would be the same. 123 Chem 24B pt of salts and buflers Revised Sp 17 4. Describe how the pH changed when the strong acid was added to Buffer 1A compared to Buffer 2A. In Buffer 1A, does the acetic acid equilibrium determine the pH or does the concentration of the strong acid determine the pH? In buffer 2A, does the acetic acid equilibrium determine the pH or does the concentration of the strong acid determine the ph? 5. Describe how the pH changed when the strong base was added to Buffer 18 compared to Buffer acid equilibrium determine the pH or does the concentration of the strong base determine the pH? In buffer 2B, does 2B. In Buffer 18, does the acetic the acetic acid uilibrium determine the pH or doos the concentration of the strong base determine the pH?

Answer 1

3) Yes, the calculated pH of buffer 1 and buffer 2 are same even at different concentrations.

Because, even when the concentrations are different, their relative ratio is the same. As this relative ratio is what affects the pH, they have the same pH

NOTE: The pH of the buffer does not get noticeably affected if the strong acid or strong base added is comparable with the concentration of conjugate base or conjugate acid present in the buffer.

4) pH will not change a lot when a strong acid is added in case of buffer 1A but will change in case of buffer 2A.

In case of buffer 1A when a strong acid is added, H⁺ in it reacts with the conjugate base present in the buffer whose concentration is comparable in the buffer. So, there will be a very little change in pH

But, the reverse is the case with buffer 2A.

Therefore in buffer 1A, acetic acid equilibrium determines the pH whereas the concentration of strong acid determines the pH in buffer 2A

5) Due to the same reason as in the explanation in NOTE.

pH will not change a lot when a strong base is added in case of buffer 1B but will change in case of buffer 2B.

In case of buffer 1B when a strong base is added, OH^- in it reacts with the conjugate acid present in the buffer whose concentration is comparable in the buffer. So, there will be a very little change in pH

But, the reverse is the case with buffer 2A.

Therefore in buffer 1B, acetic acid equilibrium determines the pH whereas the concentration of strong base determines the pH in buffer 2A