Question

The electronegativities of carbon and sulfur are almost the same. Both elements form covalently bonded compounds with hydrogen. Why is hydrogen sulfide a polar compound while methane is a nonpolar compound?

a.Sulfur has a stronger attraction for electrons than does carbon
b.A hydrogen sulfide molecule has lone pairs of electrons
c.Sulfur forms ionic bonds with hydrogen while carbon forms covalent bonds
d.Sulfur ions are larger than carbon ions

Answer 1

Hydrogen sulfide is polar because it has a bent structure with lone pairs of electrons on sulfur, causing an unequal distribution of charge. Methane is nonpolar due to its symmetrical tetrahedral shape and equal electron sharing between carbon and hydrogen atoms. So the correct option is b.

Step-by-step explanation:

The question asks why hydrogen sulfide is a polar compound while methane is a nonpolar compound, despite the fact that carbon and sulfur have almost the same electronegativities. The key difference here is the shape of the molecules and the presence of lone pairs of electrons on sulfur. Methane (CH4) has a tetrahedral geometry with carbon at the center and hydrogen atoms at the corners, with the electron sharing between the carbon and hydrogen atoms being fairly equal, resulting in a nonpolar molecule. However, hydrogen sulfide (H2S) has a bent structure due to the lone pairs on the sulfur atom, causing an unequal distribution of charge and hence, it is a polar molecule. The correct answer to the question is thus option 'b. A hydrogen sulfide molecule has lone pairs of electrons.'

Answer 2

b. A hydrogen sulfide molecule has lone pairs of electrons

Step-by-step explanation:

The presence of lone pairs indictates that the molecule will be polar unless its molecular geometry is linear or square planar. In the case of H2S, its shape is bent due to the lone pair and it is a slightly polar molecule.