Are these halides primary, secondary or tertiary? How is this determined?

1.) 2-chlorobutane
2.) 2-chloro-2-methylpropane
3.) 1-chloro-2-butene
4.) 1-chloro-2-methylpropane
5.) 1-chloroadamantane

1 Answer
Mar 27, 2018

To how many carbons is the ipso-carbon (the one bearing the #C-X# bond) attached?

Explanation:

#H_3C-stackrel("*")CHClCH_2CH_3#...the starred ipso carbon is bound to TWO other carbons...this is a #"secondary"#, #2^@# alkyl halide... it is also potentially chiral...why?

#"2-chloro-2-methylpropane"#, we got #H_3C-stackrel("*")C(CH_3)(Cl)CH_3#...the ipso carbon is attached to THREE other carbons..this is a #"tertiary"#, #3^@# alkyl halide...

#"1-chloro-2-butene"#..we gots #ClH_2stackrel"*"C-CH=CHCH_3#...the ipso carbon is PRIMARY... it is also allylic...

#"1-chloro-2-methylpropane"#, we got #ClH_2stackrel("*")C-C(CH_3)(H)CH_3#...the ipso carbon is attached to ONE other carbons..this is a #"primary"#, #1^@# alkyl halide...