Assertion: Trans isomers are more stable than cis isomers
Reason: The cis isomer is the one in which two similar group are on the same side of double bond.

In cis isomers, same or similar groups are present on the same side of double bond

In trans isomer, similar groups are present on the opposite sdie of the double bond

Draw geometrical (or cis-and trans-) isomers of the following structures and give their IUPAC names. (i) C_(2)H_(5)C CH_(3)=C CH_(3)C_(2)H_(5) (ii) CH_(3)CH_(2)CH=CHCH_(2)CH_(3) Strategy: An isomer in which two identical atoms (or groups) lie on the same sides of the double bond is called as cis isomer whereas an isomers in which identical atoms ( or groups) lie on the opposite sides of the double bond is called a trans isomer.

Cis isomer has lesser stability than the corresponding trans isomer

Cis and trans isomers generally

Cyclohexane exist as two chair conformations in rapid equilibrium at room temperature. Each carbon atom on a cyclohexane ring has one axial and one equatorial bydrogen. Rind-flipping converts axial H's to equatorial H's and vice-versa In substituted cyclohexane, groups larger than hydrogen ar more stable in the equatorial position. The cis isomers has two groups on the same side of the ring, eithere both up or both down. The trans isomer has two groups on opposite side of the ring one up and one down. Find out most stble conformer of cis-3-fluorocyclojexanol: