Consider the reaction 4e- + 4H+(aq) + O2 (g) -> (equilibrium) 2H2O (l)?

Question

Which statement is true if the hydrogen ion concentration is initially at 1.0M and the initial pressure of oxygen gas is 1.0 atmosphere

a) addition of a base should result in a value of E which is less than 1.23

b) N=1, since one mole of oxygen is being considered

c) E is independent of the pH of the solution

d) Q = [H2O]^2 / [O2]*[H+]

I need brief reasoning for each categories

Answer 1

below is the 1/2 reaction for the reduction  of O2

4e- + 4H+(aq) + O2 (g) ->  2H2O (l)

standard reduction tables state that this reaction proceeds @ standard conditions (1atm & 1 Molar), with Eo = +1.23 volts

====================================

Which statement is true if the hydrogen ion concentration is initially at 1.0M and the initial pressure of oxygen gas is 1.0 atmosphere

TRUE a) addition of a base should result in a value of E which is less than 1.23 volts,

the voltage tells you the driving force of the reaction.  LeChat's principle states that if yoiu remove a starting material, (like removinf H+ ions with a base), the reaction will shift backwards to the left,

so there would be less than the standard force of Eo = +1.23 volts for the reaction to proceed forward to the right

========================

FALSE b) N=1, since one mole of oxygen is being considered

N= 4 moles of electrons

============================

FALSE c) E is independent of the pH of the solution

E is indepentant only of the solids that are in the equilibrium,

it is very dependent upon those that are in solution, or are gases

================================

FALSE d) Q = [H2O]^2 / [O2]*[H+]

[H+] 's exponent of 4 is missing