The electromotive force E of the cell : {MexHg(1-x)MeCl(m)AgClAg} (where Me = Na, K or Cs), has been measured at the temperature 298.15 K as a function of the mole fraction x of the metal Me in amalgams and of the molality m of the alkali chloride MeCl in (ethanol + water) solvent mixtures containing up to 0.8 mass fraction of ethanol. Therefrom the respective standard electromotive forces E degrees have been determined, together with the activity coefficients gamma(+/-) of the relevant MeCl electrolyte as a function of its molality. The E degrees decrease with increasing ethanol content turns out to be the same within +/-3 mV for the three Me-amalgam cells studied.