Final answer:
The approximate bond angle in arsine (ASH3) is slightly less than 109.5 degrees due to its trigonal pyramidal shape with a tetrahedral electron pair geometry, but the closest option provided is 109.5 degrees.
Step-by-step explanation:
The bond angle in arsine (ASH3) can be predicted by considering its molecular geometry. Arsenic (As) is in group 15 of the periodic table and has a lone pair of electrons in addition to the three single bonds with hydrogen. According to the VSEPR theory, ASH3 has a molecular structure that is trigonal pyramidal, with electron pair geometry being tetrahedral. The lone pair of electrons occupies more space than the bonding pairs, which results in the bonding pairs being pushed closer together than in a perfect tetrahedral angle. A perfect tetrahedral angle is 109.5 degrees. However, due to the lone pair, the bond angle in ASH3 is slightly less than 109.5 degrees. Given the options, the closest approximate bond angle for ASH3 would therefore be less than 109.5 degrees, but since that isn't an option and taking into consideration that bond angles do not drastically deviate from the ideal tetrahedral angle, the best answer from the given choices is 109.5 degrees (Option b).