Which of the substances have polar interactions (dipole–dipole forces) between molecules? A. Cl2
B. F2
C. ClF
D. NF3

F2 and Cl2 are non-polar because both contains same atom and they have same electronegativity.

ClF and NF3 have polar interactions because there is electronegativity difference between atoms.

Explanation:

The covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements, such as hydrogen H, oxygen O and chlorine Cl. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas. The shared electron pair is common to the two atoms and holds them together.

Electronegativity is defined as the ability of an element to attract the electrons that link it to another element.

The covalent bond between two atoms can be polar or nonpolar.

When two atoms have different electronegativities, the one with the highest electronegativity will attract the electrons towards each other, giving rise to two opposite charges on the bond. That is, this generates that in a polar molecule there is separation between positive and negative charges. The bonds will be all the more polar the greater the difference in electronegativity between the bound atoms.

On the other hand, the non-polar covalent bond occurs between atoms of the same element or between atoms with very little electronegativity difference. It is thus characterized to molecules or bonds that do not exhibit any polarity.

A molecule is a dipole when there is an asymmetric distribution of electrons because the molecule is made up of atoms of different electronegativity. That is, dipole is formed when the molecule is polar.

So, dipole-dipole forces are forces of attraction between polar molecules. These molecules attract when the positive end of one of them is close to the negative of the other.

Given the above, F₂ and Cl₂ are non-polar molecules and ClF and NF₃ are polar molecules. Then ClF and NF₃ have polar interactions (dipole-dipole forces). - user

Water is polar molecule, ionic compound dissolves in it as like dissolves like.

there is ionic interaction between a salt and water

Sugar has hydroxyl group in it. These hydroxyl group are able to form hydrogen bond with water molecule.

[Hydrogen bond : the interaction between a hydrogen, bonded with a highly electro-negative element (F,O,N) and other highly electro-negative element (F,O,N)]

Thus due to hydrogen bond sugar is soluble in water.

Explanation:The water molecules, , are polar, with positive partial charges on the hydrogen and a negative partial charge on the oxygen. This makes it possible to interact with ionic compounds such as salt (NaCl). This interaction occurs through the partially positive and negative ends of the water, so that the positive charges attract the negative ones. The NaCl salt in water dissociates (separates) into  and  ions. ions are surrounded by negative partial charges of water oxygen, while  ions are surrounded by hydrogen ends with positive partial charge. In this way the salt is dissolved in water.

Sugar is a molecular compound formed by covalent bonds. In a polar covalent bond, electrons are shared unevenly. This creates a slightly negatively charged end and a slightly positively charged end. This is what happens with sugar. These extremes are those that interact with the positive and negative extremes of water, mentioned previously. Then it is possible to say that sugar dissolves in water because both substances are polar substances.

In short, water dissolves most of the substances that are polar or ionic, as in the case of sugar and salt.