Group `13` element reacts with halogen and forms a compound P shows the following properties:
(i) It is white solid and exist as dimer, gives fumes of Q with moist air
(ii) It sublimes on `180^(0)C` and forms monomer if heated to `400^(@)C`
(iii) Its aq solution turns blue litmus to red
(iv) Addition of `NH_(4)OH` and `NaOH` separately to a solution of P gives white precipitate which is however soluble in excess of `NaOH` solution to form a solution R
What is compound P
A. `B_(2)Cl_(6)`
B. `N_(2)O_(3)`
C. `(TlCl_(3))_(2)`
D. `Al_(2)Cl_(6)`
