\(CaO+H_2O\underrightarrow{t^o}Ca\left(OH\right)_2\)
\(2Na+2H_2O\rightarrow2NaOH+H_2\uparrow\)
\(Na_2O+H_2O\rightarrow2NaOH\)
\(2O_2+3Fe\underrightarrow{t^o}Fe_3O_4\)
C