Which is a polar molecule? carbon tetrafluoride [cf4] trifluoromethane [chf3] tetrachloroethylene [cl2c=ccl2] carbon tetrachloride [ccl4] ethylene [c2h4]

Trifluoromethane [CHF₃] s a polar molecule.

Explanation:

Ethylene [C₂H₄] is nonpolar because the electronegtivity difference between the C and H atom in the C-H bond is less than 0.5, making the C-H bond nonpolar.

Both carbon tetrachloride  [CCl₄] and carbon tetrafluoride [CF₄] is nonpolar. The C-F and C-Cl bonds are polar but the structure of both CCl₄ and CF₄is symmetrical, square planar, hence the polarity of each C-Cl and C-F bond in CCl4 and CF4 respectively cancel out each other making the overall molecules nonpolar.

Tetrachloroethylene [Cl₂C=CCl₂] is also nonpolar. C-Cl bond is polar but the stture of the molecule is symmetrical, linear, hence the polarity of each C-Cl  cancel out each other making the overall molecules nonpolar.

In trifluoromethane [CHF₃] the C-F bonds are polar but the C-H bond is nonpolar, and the structure of the molecule is unsymmetrical, tetrahedral. So the polarity of the two C-F bonds cancel out each other, but the polarity of the third C-F is not counteracted by the nonpolar C-H bond.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.