Among the given molecules, the only polar molecule is AsH3 (arsine).
To understand why, let’s analyze the polarity of each molecule:
- SbF5: This molecule has a trigonal bipyramidal geometry and is symmetrical. Even though it has polar bonds (Sb-F), the overall structure is nonpolar due to its shape.
- AsH3: Arsine has a trigonal pyramidal shape because of the lone pair on the arsenic atom. This shape results in an uneven distribution of charge, making it a polar molecule.
- I2: Iodine is a diatomic molecule consisting of two identical iodine atoms. Since they share electrons equally, it is nonpolar.
- SF6: Sulfur hexafluoride is a symmetrical octahedral molecule. The bond dipoles cancel each other out, resulting in a nonpolar molecule.
- CH4: Methane has a tetrahedral shape with four identical C-H bonds. Due to its symmetrical structure, it is also nonpolar.
In summary, the only polar molecule from the provided options is AsH3 due to its asymmetrical shape and the presence of polar bonds.