Open Question
A substance that changes color in the presence of an acid or base is called a(n)
439
views
18. Aqueous Equilibrium
Acid-Base Indicators
Multiple Choice
A 60.0 mL solution of 0.115 M sodium hypochlorite (NaOCl) is titrated with 0.222 M NaOH. Calculate the pH of the solution after 6.05 mL of NaOH is added. The pKa of hypochlorous acid (HOCl) is 7.53.
A
8.00
B
10.00
C
7.53
D
9.00
Verified step by step guidance1
Determine the initial moles of sodium hypochlorite (NaOCl) in the solution using the formula: \( \text{moles} = \text{volume (L)} \times \text{molarity (M)} \). Convert 60.0 mL to liters and multiply by 0.115 M.
Calculate the moles of NaOH added using the formula: \( \text{moles} = \text{volume (L)} \times \text{molarity (M)} \). Convert 6.05 mL to liters and multiply by 0.222 M.
Determine the reaction between NaOCl and NaOH. NaOH will react with NaOCl to form hypochlorite ion (OCl\(^-\)) and water. Write the balanced chemical equation for this reaction.
Calculate the new concentrations of OCl\(^-\) and HOCl after the addition of NaOH. Use the initial moles of NaOCl and the moles of NaOH added to find the change in moles and adjust the concentrations accordingly.
Use the Henderson-Hasselbalch equation to calculate the pH of the solution: \( \text{pH} = \text{pKa} + \log \left( \frac{[\text{OCl}^-]}{[\text{HOCl}]} \right) \). Substitute the values for pKa, and the concentrations of OCl\(^-\) and HOCl to find the pH.
Related Videos
Related Practice
