Solution:
There are no 3-centered-2-electron bridges in Al2Cl6(g). It has two 3-centered-4-electron bridges involving dative bonds.
Regarding the structure of Al2Cl6 (g) , false statement is
There are no 3-centered-2-electron bridges in Al2Cl6(g). It has two 3-centered-4-electron bridges involving dative bonds.