Answer
a. $HCl$
b. $NaCl$
c. $H_2$
Work Step by Step
a. The diagram shows an unsymmetrical distribution of the electron cloud corresponding to a polar bond. $HCl$ contains a polar bond because the Cl atom is slightly more electronegative than the H atom.
b. The diagram shows a cation bonded to an anion corresponding to an ionic bond. $NaCl$ contains an ionic bond because the electronegativity of Cl is so much greater than the electronegativity of Na.
c. The diagram shows a perfectly symmetric distribution of the electron cloud corresponding to a nonpolar bond. $H_2$ contains a nonpolar bond because both hydrogen atoms have equal electronegativities and attract the electrons with equal strength.
