Does boron form covalent compound or ionic?

Haber's process is used for preparation of _____.

Identify the group $14$ element that best fits the following description, forms the most acidic oxide.

Identify the group $14$ element that best fits the following description, it prefer $+2$ oxidation state.

Identify the group $14$ element that best fits the following description, it forms strong $\mathrm{\pi }$ bonds.

Give reasons, why ${\mathrm{Ga}}^{+3}$ salts are better reducing agent while ${\mathrm{Tl}}^{+3}$ salts are better oxidizing agent.