State the factor that decides the strength of an acid or a base.
- It depends on the strength of the H-A bond. The weaker the bond, the lesser the energy required to break it. Hence, the acid is strong.
- The polarity of the H-A bond affects its acid strength. If the bond is highly polar, the proton tends to leave the molecule more easily, making it a strong acid.
- However, bond strength is more important when we consider and compare acid strengths of elements in the same group of the periodic table, using the above two factors.
- Nevertheless, when we compare the acid strengths of elements in the same row, priority is given to the polarity of the H-A bond.
- The atomic size of A also affects the acid strength. As the atom becomes larger, the bond gets weaker. Consequently, acid strength increases.