Colemanite is

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?

Alumina $(Al_2O_3)$ is:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$ : Boric acid is a weak acid.
Reason $R$ : Boric acid is not able to release $H^{+}$ ion on its own. It receives $OH^{-}$ ion from water and releases $H^{+}$ ion.
In the light of the above statements,choose the most appropriate answer from the options given below.

Explain the following:
$(1)$ Gallium has higher ionisation enthalpy than aluminum.
$(2)$ Boron does not exist as $B^{3+}$ ion.

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Boron is unable to form $BF_{6}^{3-}$.
Reason $R$: Size of $B$ is very small.
In the light of the above statements,choose the correct answer from the options given below.