The common characteristic of cis-2-butene and trans-2-butene is

→ Dipolemoment α polarity α solubilityBPt depends on polarity of molecules, the polarity inturn depends upon the arrangement of groups, where as MPt depends upon the close packing of the molecules.→ In trans form the terminal groups are in opposite direction hence close packing of molecules possible, due to close packing, the contact between the molecules is more, hence attractive forces between the adjacent molecules are strong, hence inorder to break up those attractive forces we need to provide high amount of energy in the form of melting point.→ In Cis form the terminal groups are on same side, therefore close packing of molecules not possible, hence attractive forces between the molecules low, MPts low for CIS form→ hydrogenation is syn-addition, in CIS- 2-butene the addition of hydrogen(H – H) is easier due to low steric hindrance, hence heat of hydrogenation is more for CIS,  Where as in case of trans-2-butene the addition of hydrogen is difficult due to high steric hindrance between bulky methyl group and adding hydrogen, thererefore heat of hydrogenation is low for trans.