The correct order of melting points of $Al$,$Ga$,$In$ is

State the uses of aluminium and copper.

The type of hybridisation of boron in diborane is

Given below are two statements:
Statement $I$: Boron is extremely hard,indicating its high lattice energy.
Statement $II$: Boron has the highest melting and boiling point compared to its other group members.
In the light of the above statements,choose the most appropriate answer from the options given below:

Pick the correct statement.
$I$. Borax is a white crystalline solid containing $\left[B_4 O_5(OH)_4\right]^{2-}$ units.
$II$. The aqueous solution of borax is acidic in nature.
$III$. Cobalt gives a blue color in the borax bead test.

The structure of $Na_2[B_4O_5(OH)_4] \cdot 8H_2O$ contains: