Write the mechanism of dehydrohalogenation of 2-bromobutane .

Explanation

Dehydrohalogenation of 2-Bromobutane : 2- Bromobutane reacts with alc. KOH to form 2-Butene as major product .
`CH_(3)-overset(Br)overset(|)(C)H-CH_(2) - CH_3 + alc. KOH to underset(2-"Butene (major)")(CH_(3) - CH = CH- CH_(3)) + KBr + H_2 O`
Mechanism :
`to` 2-Bromobutane heated with alc. KOH elemination of hydrogen atom from `beta`-carbon and bromine atom `alpha`-carbon takes place . This is called `beta` -Elimination .

`to` 2-Butene is major formed according to saytzev's rule . "In dehydrohalogenation reactions the preferred product is that alkene which has greater no. of alkyl groups attached to double bonded carbon atoms . "