Which of the following molecules is the most polar?
Question 13 options:
a) C2H6
b) H2
c) CH3Cl
d) BF3
e) NH3
The most polar molecule out of the given options is CH3Cl (c) because it contains a polar covalent bond between the carbon and the chlorine atoms. The other molecules (C2H6, H2, BF3, and NH3) do not have polar covalent bonds.
To determine the most polar molecule, we need to assess the polarity of each molecule based on their molecular structure.
a) C2H6 (ethane) has a linear structure and consists of only nonpolar C-H bonds. Therefore, it is a nonpolar molecule.
b) H2 (hydrogen gas) consists of a nonpolar covalent bond between two hydrogen atoms. It is also a nonpolar molecule.
c) CH3Cl (chloromethane) consists of a polar C-Cl bond and nonpolar C-H bonds. Overall, CH3Cl is a polar molecule due to the presence of the C-Cl polar bond.
d) BF3 (boron trifluoride) has a trigonal planar structure and consists of three polar B-F bonds. However, the molecule's symmetrical arrangement cancels out the polarity, resulting in BF3 being a nonpolar molecule.
e) NH3 (ammonia) has a trigonal pyramidal structure and consists of a polar N-H bond. NH3 is a polar molecule because of the presence of the N-H polar bond.
Therefore, the most polar molecule among the options is CH3Cl (option c).
To determine which of the given molecules is the most polar, we need to consider the polarity of each molecule. Polarity is determined by the electronegativity difference between the atoms in a molecule.
The greater the electronegativity difference, the more polar the molecule.
Let's analyze each option:
a) C2H6 (ethane): Ethane consists of only carbon and hydrogen atoms. Carbon and hydrogen have similar electronegativities, so there is no significant electronegativity difference. Therefore, ethane is nonpolar.
b) H2 (hydrogen): Hydrogen consists of two hydrogen atoms bonded together, which is a nonpolar molecule.
c) CH3Cl (methyl chloride): Methyl chloride consists of carbon, hydrogen, and chlorine atoms. Chlorine is more electronegative than carbon and hydrogen, so there is an electronegativity difference between them. Therefore, methyl chloride is polar.
d) BF3 (boron trifluoride): Boron trifluoride consists of boron and fluorine atoms. Fluorine is more electronegative than boron, so there is an electronegativity difference. However, BF3 is a trigonal planar molecule with a symmetrical arrangement of the fluorine atoms around the central boron atom, resulting in the cancellation of dipole moments. Therefore, BF3 is nonpolar.
e) NH3 (ammonia): Ammonia consists of nitrogen and hydrogen atoms. Nitrogen is more electronegative than hydrogen, so there is an electronegativity difference. Additionally, NH3 is a trigonal pyramidal molecule with an uneven distribution of charge, resulting in a net dipole moment. Therefore, ammonia is polar.
Based on this analysis, the most polar molecule among the options is CH3Cl (methyl chloride).
Remember that determining the polarity of a molecule is based on the electronegativity difference between its atoms and its molecular geometry.