mesomeric is permanent effect

itz also called resonance

means d delocalization of double bond(pi boond)

 

electromeric is temporary effect itz due 2 addition of soem reagant

wich causes d pi bond 2 break n d elctrons shift

 

hyperconjugation is possible only wen d alpha carbon has H

d bond betwn thenm breaks n hH is left wid a positive charge

it is also called no bond  coz there no bond betwn H n C