Classify the following species into Lewis acids and Lewis bases and show how these act as Lewis acid/base?
(i) ${\mathrm{OH}}^{-}$       (ii) ${\mathrm{F}}^{-}$        (iii) ${\mathrm{H}}^{+}$            (iv) ${\mathrm{BCl}}_3$

Identify the substance that get reduced in the following reaction,

${\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)+3\mathrm{CO}\left(\mathrm{g}\right)\to 2\mathrm{Fe}\left(\mathrm{s}\right)+3{\mathrm{CO}}_2\left(\mathrm{g}\right)$

What happens when magnesium is burnt in air?

What happens when quick lime is heated with silica?