Statement – I : All decomposition reactions involving formation of the elements are redox reactions
Statement – II : ${\mathrm{CaCO}}_3\to \mathrm{CaO}+{\mathrm{CO}}_2$ Is a redox reaction

All decomposition reactions involving formation of the elements are redox reactions. But all decomposition reactions are not a redox reaction.${\mathrm{CaCO}}_3\to \mathrm{CaO}+{\mathrm{CO}}_2$ . It is a decomposition reaction but not a redox reaction.