Lower the pKa value means
Correct answer: D. Higher Ka value
- A. Strong acidic solution
- B. Lower pH of solution
- C. [OH-] > [H+]
- D. Higher Ka value
Explanation
The pKa value is the negative logarithm of the acid dissociation constant (Ka). A lower pKa value indicates a higher Ka value, suggesting that the acid dissociates more completely in solution, thus it is a stronger acid. Therefore, Option D is correct. Option A is incorrect because a strong acidic solution relates to low pH, not directly to pKa. Option B is incorrect as lower pKa does not always mean lower pH without considering the acid concentration. Option C is incorrect because a lower pKa suggests more H+ ions, not OH- ions.
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About Acids, Bases and Salts
Acid and base behaviour is explained through the Bronsted-Lowry transfer of protons and the Lewis donation or acceptance of electron pairs. The topic includes pH, pOH, ionisation and water equilibrium, plus salt formation and hydrolysis, where a salt solution may become acidic, basic or neutral.
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