Question

Why can acids give hydrogen ion very easily?

Answer 1

Acids are the substances that can donate a proton i.e. H⁺. When an acid is introduced in water, it undergoes ionisation as given below:
$\mathrm{HA}\stackrel{{\mathrm{H}}_2\mathrm{O}}{\to }{\mathrm{H}}^{+}+{\mathrm{A}}^{-}$
The H in acids are easy to remove due to weak bond between H and A. Generally A is a more electronegative atom than H, so the shared pair of electron is more towards A and the cleavage of H-A bond is easier. So, the acid donate the hydrogen ion easily. Eg. HCl. Such acids are called strong acids.
In some acids, the H cannot be readily donate as in case of acetic acid i.e. CH₃COOH, such acids are called weak acids.
The more easy the dissociation of H⁺, more stronger is the acid.