consider a standard voltaic cell based on the reaction of two moles of H plus ions reacting with one mole of 10 solid to produce one mole of 10 to ion plus hydrogen gas here, it says which of the following actions would change the E. M. F. Of the cell. So E M F. Is referring to our electro motive force which is basically our self potential here. Because we're talking about increasing or decreasing the ph that means that we're adjusting the concentration of H Plus. So we're assuming here that we're not dealing with the standard concentration of one molar. Therefore we're talking about cell potential under nonstandard conditions. So here we're gonna say using the nerds equation that are self potential under nonstandard conditions equals our self potential under standard conditions minus 0.5916 volts divided by N times log of Q. Remember Q is our reaction quotient? It equals products. Overreact ints we ignore solids within our expression, so it would be the concentration of S and two plus hydrogen here is a gas, we normally put p there to represent pressures involved for that gas divided by H. Plus and because there's a two here and B squared, we don't include the tin because it's a solid. Now we're talking about adjusting the ph we're talking about changing concentrations as well as pressures. So for the first one it says increasing the ph of the um at the cathode. Alright, realize here that whether we're increasing or decreasing the ph that means that we're having a direct impact here on the concentration of H plus, Remember that there is an inverse relationship between our reaction quotient and the overall cell potential. If our Q. Increases, that means that our overall cell potential will decrease and vice versa. So they're inversely related to each other. So doing either one of these things will affect the concentration of H. Plus. Therefore change the value of Q. And therefore change the value of our self potential or our electro motive force. If we were increasing the ph, that would mean that we're dropping the concentration of H. Plus. Because remember if you increase the ph you're becoming more basic. So this H plus would decrease which would cause an increase in Q. Which would therefore cause a decrease in your self potential. This one here lowering the ph would increase the concentration of H. Plus which would then four decrease the constant, will decrease our reaction quotient and increase our self potential. Next increasing the concentration of sn two plus at the anodes. So you're increasing the numerator here in the expression which will increase Q. And therefore decrease your self potential, increasing the hydrogen gas pressure at the cathode. So again here you're increasing H. Two now so you're increasing Q. Which will lead to a decrease in your self potential. So here the answer would be E. Because all of these actions would result in a changing of your E. M. F. Value. Just realize here because we're changing concentrations were dealing with non ideal conditions or nonstandard conditions. Therefore, we introduce the nurse equation and try to relate our reaction quotient Q to the overall cell potential.
