Question

For geometric isomers of 3hexene:

(A) M.P. is high and dipole moment high for trans.
(B) M.P. is low and dipole moment low for trans.
(C) M.P. is high and dipole moment low for trans.
(D) M.P. is low dipole moment high for trans.

Answer 1

Hint: Both properties melting point and dipole moment depend on structures of the compound, similarly in 3-hexane the two isomers have different structures altogether which result in different melting points and dipole moments.

Complete step by step answer:
Hexane is an alkene with a molecular formula of ${C_6}{H_{12}}$
There are several isomers of hexane depending upon the position and geometry of the double bond in the chain.
The isomers of 3 hexane are,

The above isomers are basically geometrical isomers of 3 hexene. One is trans isomer whereas the other is isomer.
Trans isomer is the one in which the two $x$-atoms are on the same side.
Properties of Cis - Trans isomers:
The trans isomer has a higher melting point.
The cis isomer has higher boiling point.
Cis isomers in inert solvents have strongly soluble context.
In trans isomers, a solubility is neutral solvents is smaller.
The melting point of trans isomer is higher than cis isomer, So the answer will be option C is correct.
Option C, shows that melting point is high for trans and dipole moment is law for trans which is correct.
Dipole moment in trans molecule gets cancelled whereas for cis it gets add up to give dipole moment of overall molecule.

So, the correct answer is Option C .

Note:
The properties of trans and cis isomers should be identified properly to reach upto the solution for given problem. We must also note here that the concept applied here for melting point can not be applied on boiling point, because it depends on several other factors such as H-bonding, etc.