\(2KMn{O_4}\xrightarrow{{}}{K_2}Mn{O_4} + Mn{O_2} + {O_2}\)
\(Zn + 2HCl\xrightarrow{{}}ZnC{l_2} + {H_2}\)
\(4P + 5{O_2}\xrightarrow{{}}2{P_2}{O_5}\)
\(2{H_2} + {O_2}\xrightarrow{{}}2{H_2}O\)
\(2Na + 2{H_2}O\xrightarrow{{}}2NaOH + {H_2}\)
\(3{H_2}O + {P_2}{O_5}\xrightarrow{{}}2{H_3}P{O_4}\)