Acid/Base Strength
Identify strong vs weak acids/bases, compare relative strength, and find conjugate pairs.
Common Questions
What makes an acid strong vs. weak?
Strong acids (HCl, HBr, HI, HNO3, H2SO4, HClO4) completely dissociate in water — every molecule gives up its proton. Weak acids only partially dissociate, establishing an equilibrium between the acid and its conjugate base.
What makes a base strong vs. weak?
Strong bases (group 1 and 2 hydroxides like NaOH, KOH, Ca(OH)2) completely dissociate in water. Weak bases (like NH3 and organic amines) only partially accept protons, with most molecules remaining unprotonated.
What is a conjugate acid-base pair?
A conjugate pair differs by exactly one proton. When an acid donates H+, it becomes its conjugate base. When a base accepts H+, it becomes its conjugate acid. Example: HCl/Cl- and NH3/NH4+.
How are Ka and Kb related?
For a conjugate acid-base pair, Ka x Kb = Kw = 1.0 x 10^-14 at 25°C. A stronger acid (larger Ka) has a weaker conjugate base (smaller Kb), and vice versa.