How to find out which effect(inductive(+I,-I),hyperconjugation(+H,-H),mesomeric(+M,-M) is acting on a compound???????? tell me giving some examples that in whicch compound which effect is acting .How stability depends on these effects
Mesomeric effect - This is the effect of resonance, transmitted through conjugated bonds. For example, the OH group of a phenol is strongly activating and ortho, para - directing towards electrophilic substitution in a benzene ring because of the interaction between oxygen lone pairs and the ring; you can write valence structures with a double bond between O and C, a positive charge on O, and a negative charge on the ortho or para ring carbon.
Hyperconjugation - Hyperconjugation is the stabilising interaction that results from the interaction of the electrons in a sigma-bond (usuallyC-H or C-C ) with an adjacent empty (or partially filled) p-orbital or a pi-orbital to give an extended molecular orbital that increases the stability of the system.