Decomposition efficiency ($\eta _{D}$) of an electrolytic cell used for producing $NaOH$ is defined as ​​​​​​

1. $\eta _{D}$ = (grams of $NaOH$ produced / grams of $NaCl$ decomposed) $\times$ 100
2. $\eta _{D}$ = (grams of $NaOH$ produced / grams of $NaCl$ charged) $\times$ 100
3. $\eta _{D}$ = (gram equivalents of $NaOH$ produced / gram equivalent of $NaCl$ charged) $\times$ 100
4. $\eta _{D}$ = (theoretical current to produce one gram equivalent / actual current to produce one gram equivalent) $\times$ 100

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