7. Calculate the pH of a 0.0010 M solution of sodium salicylate, C_(6)H_(4)(OH)COONa 8. Suppose you have 100 mI of a buffer containing 0.100 M acetic acid and 0.0500 M sodium acetate . Calculate the pH of the buffer when 3.00 mL of 1.00 M HCl is added to it. 40 minutes How many

7. To calculate the pH of a 0.0010 M solution of sodium salicylate ($C_{6}H_{4}(OH)COONa$), we need to use the Henderson-Hasselbalch equation:<br /><br />pH = pKa + log([A-]/[HA])<br /><br />where pKa is the acid dissociation constant of the conjugate acid (salicylic acid), [A-] is the concentration of the conjugate base (salicylate ion), and [HA] is the concentration of the acid (salicylic acid).<br /><br />The pKa of salicylic acid is approximately 3.1. Since the concentration of the conjugate base (salicylate ion) is much greater than the concentration of the acid (salicylic acid), we can assume that the pH of the solution will be close to the pKa of salicylic acid.<br /><br />Therefore, the pH of the 0.0010 M solution of sodium salicylate will be approximately 3.1.<br /><br />8. To calculate the pH of the buffer after adding 3.00 mL of 1.00 M HCl, we need to first calculate the new concentrations of acetic acid and sodium acetate in the buffer.<br /><br />Initial concentration of acetic acid = 0.100 M<br />Initial concentration of sodium acetate = 0.0500 M<br /><br />Volume of buffer = 100 mL<br />Volume of HCl added = 3.00 mL<br /><br />New concentration of acetic acid = (0.100 M * 100 mL) / (100 mL + 3.00 mL) = 0.0947 M<br />New concentration of sodium acetate = (0.0500 M * 100 mL) / (100 mL + 3.00 mL) = 0.0476 M<br /><br />Now, we can use the Henderson-Hasselbalch equation to calculate the pH of the buffer:<br /><br />pH = pKa + log([A-]/[HA])<br /><br />where pKa is the acid dissociation constant of acetic acid (approximately 4.7), [A-] is the concentration of the conjugate base (acetate ion), and [HA] is the concentration of the acid (acetic acid).<br /><br />pH = 4.7 + log(0.0476 / 0.0947)<br />pH ≈ 4.7 + log(0.5)<br />pH ≈ 4.7 - 0.3<br />pH ≈ 4.4<br /><br />Therefore, the pH of the buffer after adding 3.00 mL of 1.00 M HCl will be approximately 4.4.