Final answer:
The student asked about balancing a redox reaction in an acidic solution and finding the number of oxygen atoms on the right-hand side. The reaction involves Cr2O7 and S2O3 ions. The balanced equation results in 7 oxygen atoms from water molecules, with additional oxygen counts dependent on the oxidation product of thiosulfate.
Step-by-step explanation:
The question deals with a redox reaction where dichromate ion (Cr2O72-) reacts with thiosulfate ion (S2O32-) in an acidic solution. To find out how many oxygen atoms are on the right-hand side of the balanced chemical equation, we need to balance the equation first.
The balanced half-reaction for dichromate in an acidic medium is:
Cr2O72- + 14H+ + 6e- → 2Cr3+ + 7H2O
And for thiosulfate:
S2O32- → S4O62- + 2e-
Combining these two half-reactions and canceling electrons, we get the overall balanced equation:
Cr2O72- + 14H+ + 3S2O32- → 2Cr3+ + 7H2O + 3S4O62-
The number of oxygen atoms on the right side of this balanced equation is 7 (from the water molecules) plus the oxygen atoms in the thiosulfate's oxidation product (which needs to be determined).