Identify the $P$ and $Q$ of the following reaction: $P + Q \longrightarrow [B(OH)_4]^{-} + H_3O^{+}$

Given below are two statements :
Statement $I$ : Gallium is used in the manufacturing of thermometers.
Statement $II$ : $A$ thermometer containing gallium is useful for measuring the freezing point $(256 \ K)$ of brine solution.
In the light of the above statement,choose the correct answer from the options given below :

The chemical name of borax is

Boron forms $BX_3$ type of halides. The correct increasing order of Lewis-acid strength of these halides is

Boron compounds act as Lewis acids due to their .....

An element $X$ which occurs in the first short period has an outer electronic structure $s^2p^1$. What are the formula and acid-base character of its oxides?