Calculate the heat required to convert $3kg$ of ice at $-12^{o}C$ kept in a calorimeter to steam at $100^o$ at atmospheric pressure. (Given: specific heat of ice $=2.100\times 10^{5}Jk{g}^{-1}{K}^{-1}$, specific heat of water  $=4.186\times 10^{6}Jk{g}^{-1}$, latent heat of fusion of ice $=3.35\times 10^{5}Jk{g}^{-1}$ and latent heat of steam $=2.256\times 10^{6}Jk{g}^{-1}$) . 

A thermally isolated vessel contains $100g$ of water at $0^{o}C$ When air above the wall pumped out, some of the water freezes and some evaporates at $0^{o}C$ itself. Calculate the number of the ice formed if no water is left in the vessel. Latent heat of vaporization of water $0^{o}C=\times 10^{6}Jk{g}^{-1}$ and latent heat of fusion of ice $=3.36\times 10^{5}Jk{g}^{-1}$