1) The main oxides formed on combustion of Li, Na, and K in excess of air respectively are A) $LiO_{2}$,$Na_{2}O_{2}$and $K_{2}O$ B) $Li_{2}O_{2}$,$Na_{2}O_{2}$and$ KO_{2}$ C) $Li_{2}O$,$Na_{2}O_{2}$ and $KO_{2}$ D) $Li_{2}O$ ,$Na_{2}O$ and $KO_{2}$ Answer: Option CExplanation:$2Li +\frac{1}{2}O_{2}(g)\rightarrow Li_{2}O$ $2Na+ O_{2}(g)\rightarrow Na_{2}O_{2}$ $K+O_{2}(g)\rightarrow KO_{2}$
