Question

Among the following mixture maximum dipole-dipole interaction is present in?
(A) Benzene and ethanol
(B) Acetonitrile and acetone
(C) $KCl$ and water
(D) Benzene and carbon tetrachloride

Answer 1

Hint:In order to check dipole- dipole interaction see whether both the molecules of the mixture are polar or not. When two dipolar molecules connect with each other across space, Dipole-Dipole interactions occur. The partly negative portion of one of the polar molecules is drawn to the partly positive portion of the second polar molecule as this happens.

Complete answer:
Let us first understand what is dipole-dipole interaction;
-The direct interaction between two magnetic dipoles refers to the magnetic dipole-dipole interaction, also known as dipolar coupling. Due to the unequal distribution of electrons among atoms in a molecule, molecular dipoles occur. The bonded electrons are taken closer to themselves by certain atoms that are more electronegative. The aggregation of electron density around an atom or a distinct area of a molecule will result in a molecular dipole that has a partially negative charge on one side of the molecule and a partially positive charge on the other side.
-To check solution to our question ;
-Considering option (A) benzene is a nonpolar molecule and ethanol $C{H}_3-OH$ will be a polar molecule but this does not form dipole- dipole interaction as one is polar and other nonpolar
-Option (B) acetonitrile and acetone , here acetonitrile is a highly polar compound and acetone is also polar here making it a polar-polar interaction or dipole dipole interaction also both this molecules have a hydrogen -hydrogen bond acceptor but neither of them have a hydrogen bond donor so they will interact through their polar region making it a dipole–dipole interaction .
-So option (B) will be correct
-In option(C) there is $KCl$with $K^{+}-C{l}^{-}$ ionic bond and $H_{2}O$ will be polar so this will form ion-dipole interaction
-In option (D) benzene have carbon-hydrogen bond so it will be non-polar covalent molecule
-And for carbon tetrachloride carbon-chlorine bond it is also non polar molecule , when we check dipole moment of $CC{l}_4$ it will cancel out each other and will be zero, there will be no dipole-dipole interaction
Hence, Option B is correct.

Note:
Many physically and biologically relevant phenomena, such as the elevated boiling point of water, account for this form of dipole-dipole interaction between molecules. In contrast to covalent bonds within a molecule between atoms (intramolecular bonding), dipole-dipole interactions create attractions within a substance 's molecules (intermolecular attractions).