Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
Thallium(III) can oxidise tin(II) to tin(IV) in a two-electron reaction: . The standard potential is for Tl changing to Tl, and for Sn changing to Sn. Find the cell potential, the energy that the reaction releases for each mole in kJ, and at 298 K.
For a redox reaction, , with , and at 298 K, . A reaction goes if is positive. Moles of reactant come from mass divided by molar mass, and the equation gives the ratios.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Plan. Subtract the potentials. Then use .
Step 1. Cell potential. .
Step 2. Energy released. .
Step 3. The constant. .
Answer: , and .
Check. The cell potential is positive, so the reaction goes, and is so large that it runs to the end. This is the inert pair effect: thallium(III) is eager to become thallium(I).
Source. The standard potentials are standard values from the CRC Handbook of Chemistry and Physics.
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