Answer:
HOCl is such a weak acid that the basicity of the OCl⁻ predominates in the mixture.
Explanation:
HOCl is a weak acid with pKₐ 7.53. NaOCl is its salt. A solution of a weak acid and its salt is a buffer. We can calculate the pH of the buffer.
Step 1. Write the equation for the equilibrium
HOCl + H₂O ⇌ H₃O⁺ + OCl⁻; pKa = 7.53
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Step 2. Calculate the pH of the buffer
The Henderson-Hasselbalch equation is
pH = pKₐ + log([OCl⁻]/[HOCl])
pH = 7.53 + log(0.15/0.15)
pH = 7.53 + log1
pH= 7.53 + 0
pH = 7.53
So, the solution is basic.
The conjugate base of a weak acid is a relatively strong base.
HOCl is such a weak acid that the basicity of its conjugate base predominates in an equimolar mixture of the two components.