pH stands for
the power of hydrogen. pH that ranges form 1-6.9 are acid substances. At pH 1 -
2.9, the substance is highly acidic which will have the color from red to red - orange. At pH 3 - 4, the substance is mildly
acidic and the color range is from red - orange to orange. At pH 4.1 – 6.9, the substance is weakly acidic and the color range is from orange to yellow. At pH 7, it is
neutral and it is green in color. At pH 7.1-14, it is basic. At pH 7.1 - 10.9, the substance is weakly
basic the color range is from green to blue. At pH 11 - 13, the substance is mildly basic and the color range is from blue to purple. At pH 13.1 – 14, the
substance is highly basic and the color range is from purple to light purple.
Answer:
Part A. The half-cell B is the cathode and the half-cell A is the anode
Part B. 0.017V
Explanation:
Part A
The electrons must go from the anode to the cathode. At the anode oxidation takes place, and at the cathode a reduction, so the flow of electrons must go from the less concentrated solution to the most one (at oxidation the concentration intends to increase, and at the reduction, the concentration intends to decrease).
So, the half-cell B is the cathode and the half-cell A is the anode.
Part B
By the Nersnt equation:
E°cell = E° - (0.0592/n)*log[anode]/[cathode]
Where n is the number of electrons being changed in the reaction, in this case, n = 2 (Sn goes from S⁺²). Because the half-reactions are the same, the reduction potential of the anode is equal to the cathode, and E° = 0 V.
E°cell = 0 - (0.0592/2)*log(0.23/0.87)
E°cell = 0.017V
