The stability of 2, 3 - dimethyl but -2- ene is more than 2-butene. This can be explained in terms of

The effect that makes 2,3-dimethyl-2-butene more stable than 2-butene is :

3,3-dimethyl-1-butene

The effect that makes 2, 3–dimethyl-2-butene more stable than 2-butene is :-

Assertion : 2,3- dimethyl but -2- ene is more stable than but -2- ene. Reason : 2,3- dimethyl but -2- ene possesses 12 alpha- hydrogen atoms whereas but -2- ene possesses only 6 alph- hydrogen atms and therefore former shows more pronounced hyperconjugation.

2-methylpropene is isomeric with butene-1. They can be distinguished by:

Bond angle in dimethyl ether is more than that in water.

Assertion : 2,3-Dimethylbut-2-ene is more stable than but-2-ene. Reason : Six hyperconjugation structures can be written for 2, 3-dimethylbut-2- ene while but-2-ene has twelve.