Which of the following expression is correct?

Correct answer: C. Ka × Kb = 10-14

  • A. Ka × Kb = pKw
  • B. Ka × Kb = 14
  • C. Ka × Kb = 10-14
  • D. Ka × Kb = 1014

Explanation

The correct relationship between the ionization constants of an acid and its conjugate base is given by Ka × Kb = Kw. At 25°C, the ionization constant of water (Kw) is 10-14. Therefore, the expression Ka × Kb = 10-14 is correct. Option A is incorrect because it confuses Kw with its logarithmic form pKw. Option B is incorrect as it incorrectly equates the product to 14 instead of 10-14. Option D is incorrect because it incorrectly displays the product as 1014, which is the inverse of the correct value.

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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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