Which of the following molecules is polar? NCl3, NO2, H2S, or SiH4
http://users.stlcc.edu/gkrishnan/polar.html
SiH4
Harsha
To determine if a molecule is polar or nonpolar, you need to consider its molecular structure and the polarity of its individual bonds.
Polarity is a measure of the distribution of electron density in a molecule. If there is a significant difference in electronegativity between the atoms forming a bond, the bond will have a polar character. A polar bond contains a positive and negative pole, with electrons being drawn closer to the more electronegative atom.
Additionally, the overall polarity of a molecule depends on its molecular geometry. If the polar bonds in a molecule are symmetrically arranged, they can cancel each other out, resulting in a nonpolar molecule. On the other hand, if the polar bonds are not symmetrical, the molecule will be polar.
Now, let’s apply this knowledge to the given molecules:
1. NCl3 (Nitrogen Trichloride):
Nitrogen (N) is less electronegative than Chlorine (Cl), so N-Cl bonds are polar. NCl3 has a trigonal pyramidal shape, with the nitrogen atom at the center and three chlorine atoms surrounding it. Since the molecule is not symmetrical, the individual polar bonds do not cancel each other out, making NCl3 a polar molecule.
2. NO2 (Nitrogen Dioxide):
Nitrogen (N) is less electronegative than Oxygen (O), so N-O bonds are polar. NO2 has a bent molecular shape, with the nitrogen atom at the center and two oxygen atoms on either side. Since the molecule is not symmetrical, the individual polar bonds do not cancel each other out, making NO2 a polar molecule.
3. H2S (Hydrogen Sulfide):
Hydrogen (H) is less electronegative than Sulfur (S), so H-S bonds are polar. H2S has a bent molecular shape, with the sulfur atom at the center and the two hydrogen atoms on either side. Since the molecule is not symmetrical, the individual polar bonds do not cancel each other out, making H2S a polar molecule.
4. SiH4 (Silane):
Silicon (Si) is less electronegative than Hydrogen (H), so Si-H bonds are polar. SiH4 has a tetrahedral molecular shape, with the silicon atom at the center and four hydrogen atoms surrounding it. Since the molecule is symmetrical, the individual polar bonds cancel each other out, making SiH4 a nonpolar molecule.
So, out of the given molecules, NCl3, NO2, and H2S are polar, while SiH4 is nonpolar.