Question

A strong acid has conjugate 
1. Strong base
2. Weak base
3. Strong acid
4. Weak acid

Answer 1

Correct Answer - Option 2 : Weak base

The correct answer is Weak base.

• According to Bronsted–Lowry acid-base theory, the stronger of a pair of acids must form the weaker of a pair of conjugate bases.
  • ​Therefore, the conjugate base of a strong acid is a weak base. 

• A Bronsted-Lowry acid is a substance that
  • donates a proton or H+ ion to the other compound and forms a conjugated base.
• A Bronsted-Lowry base is a substance that
  • accepts a proton or H+ ion from the other compound and forms conjugated acid.
• Strong acids and bases ionize completely in an aqueous solution, whereas weak acids and bases are partially ionized in an aqueous solution.
• Water molecule is amphoteric in nature, which means it can act as Bronsted-Lowry acid as well as Bronsted-Lowry base.
• The Bronsted-Lowry theory is an extended version of an Arrhenius theory of acid-base.
• According to the Arrhenius theory, in an aqueous solution, acid increases the concentration of H+ ions and base increases the concentration of OH– ions. The limitations of Arrhenius theory were, it identifies the reaction of an acid and base only in the aqueous medium.
• Strong Bronsted-Lowry acids are those which have a strong tendency to give a proton and their corresponding conjugate base is weak.
• Weak Bronsted-Lowry acids will have a little tendency to donate a proton and their corresponding conjugated base is strong.