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If more concentrated NaOH is used during standardization would the pKa change?

Benzoic acid is an organic acid with a Ka of 6.5x10^-5. It can also be used as a primary standard like KHP. If benzoic acid were used to standardize NaOH, determine if if the equivalence point is acid, basic, or neutral based on the following criteria?:

pKa < 0 is strong acid
1<pKa< 10 weak acid
pKa > 10 very weak

If more concentrated NaOH is used during standardization could this change any of these results or is the pKa a constant?

Solution Preview

pKa<0 -> Ka > 1 which means I have a very strong acid.

1<pKa<10 -> 0.1 > Ka > 10-10 which means I have weak acid. [H+] is more than 10-5

pKa>10 -> Ka > 10-10 which means I have very very weak acid. [H+] is less than 10-5
Note: {[H+] ...

Solution Summary

At the equivalence point, all base and acid react with each other and the products are salt and water. See solution for full explanation and answers.

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