A student measures the potential for cells containing A+B+and C+ ions and their metals and records his data in the table below:
............. Overall Reaction ................Potential (V)
Cell#1'''''''A(s) A+(aq) B+(aq) B(s)''''''''''''0.90
Cell#2''''''A(s) A+(aq) C+(aq) C(s)''''''''''''0.25
Cell#3''''''C(s) C+(aq) B+(aq) B(s)''''''''''''' 0.65
Which ion (A+B+C+) reduces the easiest?
A. A+
B. C+
C. B+
For the cell: A(s) A+(aq) C+(aq) C(s). If the concentration of C+ decreases, the cell potential,
Ecell, will______ (increase or decrease), because Q value for the reaction will_______ (increase or decrease).
For the cell: C(s) C+(aq) B+(aq) B(s).
Metal________ is the "negative" electrode.
B+
decrease
increase
C(s)
Vin is correct(:
Vin is correct!
vin is right :)
a+b+c=245,b=4a,c=(a+b+c):5
To determine which ion reduces the easiest, we need to compare the potential values recorded in the table. The ion with the highest potential (V) reduction would be the easiest to reduce.
In this case, the potential values for the cells are as follows:
Cell #1: A(s) A+(aq) B+(aq) B(s) - Potential: 0.90 V
Cell #2: A(s) A+(aq) C+(aq) C(s) - Potential: 0.25 V
Cell #3: C(s) C+(aq) B+(aq) B(s) - Potential: 0.65 V
Comparing the potential values, we see that the lowest potential is recorded for Cell #2 (0.25 V), where C+ is present. Therefore, the ion C+ reduces the easiest.
Answer: B. C+
Regarding the effect of decreasing the concentration of C+ for the cell A(s) A+(aq) C+(aq) C(s), we need to consider the Nernst equation:
Ecell = E°cell - (RT / nF) * ln(Q)
In the Nernst equation, Ecell represents the cell potential, E°cell represents the standard cell potential, R is the gas constant, T is the temperature, n is the number of electrons transferred in the balanced cell reaction, F is the Faraday constant, and Q is the reaction quotient.
As C+ is a product in this cell, decreasing its concentration would result in a decrease in the reaction quotient, Q. Since ln(Q) would be negative, subtracting a negative term in the Nernst equation leads to an increase in Ecell.
Therefore, decreasing the concentration of C+ would increase the cell potential, Ecell.
For the cell C(s) C+(aq) B+(aq) B(s), the metal that acts as the "negative" electrode would be C(s).
Answer: C(s)