(a) Standard electrode potential value `E^@` for `Al^(3+)//Al` is `- 1.66 V` and that of `Tl^(3+)//Tl` is `+ 1.26 V`. Predict about the formation of `M^(3+)` ion in solution and compare the electropositive character of the two metals.
(b) White fumes appear around the bottle of anhydrous aluminium chloride. Give reason.
( c) Boron is unable to form `BF_(6)^(3-)` ion. Explain.

Explanation

Standard electrode potential values for two half cell reactions suggest that aluminium has high tendency to make `Al^(3+)` (aq) ions, whereas `Ti^(3+)` is not only unstable in solution but is a powerful oxidising agent also Thus `Ti^(+)` is more stable in solution than `Tl^(3+)`, Aluminium being able to form +3 ions easily, is more electropositive than thallium.