For the properties mentioned, the correct trend for the different species is in

Options

A. strength as Lewis acids -
`BCl_(3) gt AlCl_(3) gt GaCl_(3)`
B. inert pair effect - `Al gt Ga gt In`
C. oxidising property `-Al^(3+) gt Ga gt In`
D. first ionization enthalpy `-B gt Al gt Tl`

Answer

A

Explanation

Only option (a) , i.e., strength of Lewis acids decreases in the order : `BCl_(3) gt AlCl_(3) gt GaCl_(3)` is correct while all other options are incorrect as explained below :
Al does not show inert pair effect, `Tl^(3+)` has the highest oxidising power while ionization enthalpy of Tl is higher than that of Al.