Question

17.
which is the lewis structure for silicon disulfide?
a. :s::si::s:
b. s::si::s
c. s:si:s
d. :s:si:s:
18.
which compound is nonpolar?
a. h₂s
c. sih₃cl
b. ccl₄
d. ash₃

1. which formulas and their respective names do not match?

i) bao - barium hydroxide
ii) ccl₄ - carbon tetrachloride
iii) n₂o₄ - dinitrogen tetroxide
iv) hf - monohydrogen monofluoride
a. i and ii
c. ii and iii
b. i and iv
d. i, iii, and iv

Explanation:

Question 17

Silicon has 4 valence electrons and sulfur has 6 valence electrons. In silicon disulfide (\(SiS_2\)), silicon forms double bonds with each sulfur atom. In Lewis structure, each sulfur atom has 2 lone pairs. Option A shows the correct bonding and lone - pair distribution.

• For \(H_2S\), it has a bent shape (similar to \(H_2O\)) due to the lone pairs on sulfur, making it polar.
• \(CCl_4\) has a tetrahedral shape. Since all the \(C - Cl\) bonds are identical and the dipoles cancel out, it is non - polar.
• \(SiH_3Cl\) has a tetrahedral shape but the \(Si - H\) and \(Si - Cl\) bonds have different polarities and the dipoles do not cancel.
• \(AsH_3\) has a trigonal pyramidal shape (due to the lone pair on As) and is polar.

• \(BaO\) is barium oxide, not barium hydroxide (\(Ba(OH)_2\)).
• \(CCl_4\) is carbon tetrachloride (correct).
• \(N_2O_4\) is dinitrogen tetroxide (correct).
• \(HF\) is hydrogen fluoride (not monohydrogen monofluoride, which is an incorrect naming convention for a simple binary acid).

Answer:

A. \(:S::Si::S:\)

Question 18