Chapter 7: PROBLEM 7.25 (page 273)

Question: Classify each carbocation as $1 °$ , $2 °$ , $3 °$ .
a.
b.
c.
d.

Short Answer

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Answer

a. The given carbocation is $2 °$ .

b. The given carbocation is $1 °$ .

c. The given carbocation is $3 °$ .

d. The given carbocation is $2 °$ .

Step by step solution

Carbocations

Carbocations were formerly called “carbonium ion.” These species belong to the category of reactive intermediates.

Classification of carbocations into 1° , 2° and 3°

Electron-deficient carbons linked to one carbon atom can be referred to as primary ( $1 °$ ) carbocations. Secondary( $2 °$ ) and tertiary( $3 °$ ) carbocations are species where the electron-deficient carbon is joined to two and three carbon atoms, respectively.

Identification of carbocations as 1° ,2°and 3°

a. The carbocation structure consists of a carbon atom possessing a positive charge linked to two other carbon atoms. Hence, this carbocation is a $2 °$ carbocation.

b. The carbocation structure comprises a carbon atom with a positive charge linked to another carbon atom. Hence, this carbocation is a $1 °$ carbocation.

c. The carbocation structure contains a carbon atom comprising a positive charge linked to three other carbon atoms. Hence, this carbocation is a $3 °$ carbocation.

d. The carbocation structure contains a carbon atom with a positive charge joined to two other carbon atoms. Hence, this carbocation is a $2 °$ carbocation.