To solve this problem, we need to analyze the structure and properties of $PCl_5. \\$1. $PCl_5$ has a trigonal bipyramidal structure. In this structure:$\\$• There are three equatorial P-Cl bonds and two axial P-Cl bonds.$\\$2. Let's evaluate each option:$\\$• Option 1: Three equatorial P-Cl bonds make an angle of $120^\circ$ with each other.$\\$ - This is correct. In a trigonal bipyramidal structure, the equatorial bonds are $120^\circ$ apart.$\\$• Option 2: Two axial P-Cl bonds make an angle of $180^\circ$ with each other.$\\$ - This is correct. The axial bonds are linear and $180^\circ$ apart.$\\$• Option 3: Axial P-Cl bonds are longer than equatorial P-Cl bonds.$\\$ - This is correct. Due to greater repulsion, axial bonds are typically longer than equatorial bonds.$\\$• Option 4: $PCl_5$ molecule is non-reactive.$\\$ - This is incorrect. $PCl_5$ is reactive, especially with water, where it hydrolyzes to form $H_3PO_4$ and $HCl. \\$Therefore, the incorrect statement is Option 4. $PCl_5$ is reactive.$\\$