The voltage relationships for several different reference electrodes at 25 °C can be interrelated as follows:For example, if one measured 300 mV using a saturated KCl Ag/AgCl reference(ref2) and wanted to refer it to the standard reduction potential (formula_2) measured using a SHE reference electrode (ref1), then 192 mV should be added to the 300 mV to obtain 492 mV, sinceformula_10it follows thatformula_11and thereforeformula_12Likewise, if one measured 300 mV using a saturated KCl Ag/AgCl reference (ref2) and wanted to determine the corresponding measurement using an SCE reference (ref1), then givenformula_10it follows thatformula_11and thereforeformula_15==Half cells==The relative reactivities of different half cells can be compared to predict the direction of electron flow.