$14{H^ + } + C{r_2}O_7^{2 - } + 3Ni \to 2C{r^{3 + }} + 7{H_2}O + 3N{i^{2 + }}$
$Cr _2 O _7^{2-}+ XH ^{+}+6 Fe ^{2+} \rightarrow YCr ^{3+}+6 Fe ^{3+}+ ZH _2 O$
$X , Y$ અને $Z$ નો સરવાળો $......$ છે.
${H_2}O + B{r_2} \to HOBr + HBr$
$5{H_2}{O_2} + \,xCl{O_2}\, + 2O{H^ - }\, \to \,xC{l^ - }\, + \,y{O_2} + 6{H_2}O$
${H_2}{O_2}\xrightarrow{{R.T}}{H_2}O + \frac{1}{2}{O_2}$