Addition of HX on alkene proceed through formation of carbocation . This reaction is follows Markovnikov's rule. According to markovnikov's rule addition of electrophile occurs on that carbon of alkene which have more number of -H atom
`Ph-CH = CH_2 underset(HX)to underset("(major)")(Ph-overset(x)overset(|)CH-CH_3) + underset("(minor)")(Ph-CH_2-CH_2-X)`
Which of the following alkenes will give markovnikov's reaction ?

Options

A. `P gt Q gt R gt S `
B. `R gt Q gt P gt S`
C. `S gt R gt Q gt P`
D. `Q gt R gt P gt S`

Answer

B

Explanation

Stability of intermediate carbocation given in the following



N.atom is less electro negative. So loan pair of nitrogen atom participating in resonance then oxygen atoms so 1 is more stable than 2, 4 is less table because of -I effect of `-OCH_3`