Which one of the following has the highest standard molar entropy at 25 degrees c? a) nabrb) nafc) nacld) naie) they have the same value

d) NaI

Explanation:

The entropy is the measure of the randomness of a substance, as higher is it, higher is the entropy. For a covalent bond (bond between a metal and a nonmetal), when the bond is strong, the entropy will be small, when it is weak, the entropy will be higher because the atoms will be "free" to move, and the randomness will be greater.

The force of the bond increases when the electronegativity difference increases. In the groups, the electronegativity increases from the bottom to the top, so for group 7: F > Cl > Br > I.

Then the difference of electronegativity is small at NaI, which has the highest standard molar entropy.