40. Solving a chemistry problem

10. Having the electrode specified in the task, it is necessary to select the second metal electrode and calculate the concentration of salt - electrolyte (taking into account ƒ or α) in order to obtain the specified value of the EMF of the galvanic cell, composed of the electrode specified in the task and selected by you. Write an electrochemical circuit of a galvanic cell. Indicate which electrode is the anode and which is the cathode. Write the equations for reactions occurring at the anode and cathode.
Pt, H2 / 0.01M HNO2 α = 0.21; EMF = 1.661 V