CGPET 2019 Solved Paper

Key Point The carbon, which is bonded with four different atoms/groups is known as chiral carbon.
The structure of the given IUPAC names are as follows:
(a) 3 -methylhexane
C

6

H3

−C

5

H2

−C

4

H2

−

3 CH |

CH3

−C

2

H2

−C

1

H3

or C3H7−•

H | C |

CH3

−C2H5
(It has one chiral carbon atom, marked with dot.)
(b) 2 -methylhexane

6

H3

C−C

5

H2

−C

4

H2

−C

3

H2

2

−

H | C |

CH3

−C

1

H3

It has no chiral carbon atom.
(c) 2, 4-dimethyl pentane

5

H3

−C

4 H |

CH3

−C

3

H2

−C

2 H |

CH3

−C

1

H3

It has also no chiral carbon atom.
(d) 2 -methyl pentane
H3

5

C

−C

4

H2

−C

3

H2

−C

2 H |

CH3

−C

1

H3

It has also no chiral carbon atom.
Thus, option (a) is the correct answer.