alleryStart learning →At what pH does the equivalence point fall when a strong acid is titrated with a strong base?
ABelow 7.00, since the acid dominates
BAbove 7.00, since the base is stronger
CExactly 7.00 at standard temperature
DIt depends on the concentrations used
Answer & Solution
Correct answer: C. Exactly 7.00 at standard temperature
1. At equivalence the hydronium from the acid and the hydroxide from the base cancel exactly.
2. The salt formed has ions of negligible acid and base strength, so neither shifts the pH.
3. The only hydronium left is what the autoionisation of water supplies.
4. That gives 1.0 x 10^-7 mol per litre, so the pH is 7.00.
5. A weak acid changes this, but for two strong reagents the value is fixed.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 14 "Acid-Base Equilibria", section 14.7 Acid-Base Titrations_
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