Question

Put the following three molecules in order of increasing H-X-H bond angle, where X is the central atom. CH4 Has PH3 A. CH4 < H2S < PH3 | B. H2S • PH3 – CHA C. CH4 < PH3

Answer 1

Step-by-step explanation:

Answer C. CH4 < PH3 < H2S

The H-X-H bond angle generally decreases as the central atom X increases in size or electronegativity. Therefore, we can rank the three molecules in order of increasing H-X-H bond angle as follows:

C. CH4 < PH3 < H2S

In methane (CH4), the central atom (C) is the smallest and least electronegative, so the H-C-H bond angle is the largest at approximately 109.5 degrees. In phosphine (PH3), the central atom (P) is larger and more electronegative than carbon, so the H-P-H bond angle is smaller at approximately 93.5 degrees. In hydrogen sulfide (H2S), the central atom (S) is even larger and more electronegative than phosphorus, so the H-S-H bond angle is the smallest at approximately 92 degrees. Therefore, the correct order is: