The basis of Markovnikov's addition is the stability of the intermediate carbocation formed. The addition occurs through more stable carbocation intermediate.

In case of dienes the 1,2-addition product is the result of more stable carbocation; while the 1,4-addition product is because of the rearranged carbocation.The 1,2- & 1,4- addition products is based on following facts:

1.Eact. for 1,2-addition product is lower than that for 1,4-addition product.

2.The relative amounts of the two products are goverened by their relative rates, at low temp. the reaction is kinetically controlled.

3.At higher temp. the 1,4-product predominates over 1,2-product, suggests that 1,4-addition product is thermodynamically more stable than 1,2-product.

4.Each product(1,2- &1,4-)is converted to the same mixture on heating as a result of equilibrium between the products