can you explain with examples - ortho effect?

Theortho effectis the effect caused on the nature of the compound of the ring system in which the substituent are at ortho -position i.e. just next to the functional group. This effect does not depends on the electron donating or electron withdrawing nature of the substituent but the effect is caused due to the steric hinderance which makes the molecule unstable.

For ex: in Benzoic acid, ortho substituted benzoic acid is more acidic than meta/para substituted benzoic acid as it is sterically hindered by the substituent group which makes it unstable and thus the acid could release proton easily and the acidic nature becomes strong.