Sodium benzoate and benzoic acid are mixed in equimolar ratio to form buffer if pKa is 2 what will be the pH ?
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Answer: C. 2
Explanation
The Henderson-Hasselbalch equation shows that equimolar weak acid and conjugate base concentrations yield pH equal to pKa. Logarithm of one equals zero, making the pH value directly equal to the given pKa number. Equimolar buffer solutions maintain a stable pH that matches the negative logarithm of the acid dissociation constant. Buffer solutions resist drastic changes in pH when small amounts of strong acids or bases are added. Benzoic acid and sodium benzoate form a classic weak acid and salt buffer system. The pKa value is a quantitative measure of acid strength in aqueous chemical solutions.
Biochemical assays and pharmaceutical formulations require precise buffer systems to maintain stable pH. Laboratory experiments utilize buffers to calibrate pH meters and control reaction environments. Understanding buffer calculations is essential for managing chemical equilibria in industrial processes. A pH of zero corresponds to a very strong acid solution rather than an equimolar buffer. A pH of one fails to account for the equimolar ratio where pH precisely equals pKa. Choosing any one is incorrect because buffer mathematics strictly dictates a precise numerical pH outcome.
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