Question

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

Answer 1

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...