Hard Acid or/also Strong acid?

[adianadiadi]

Whether a hard acid is a stronger acid?

I mean if we take soft acid, is it weak?

[spirochete27]

Strong/Weak and hard/soft are two totally different concepts. Strength and weakness of an acid is measured by its thermodynamic tendency to give up protons. Google "hard soft acid base theory" for an explanation of the latter. HSABT can be a kinetic concept, while strong/weak is mainly a thermodynamic descriptor measured by the equilibrium constant K_a.