Answer the following questions that refer to the unbalanced reaction shown below as it occurs in acidic solution:
_______ Cr 2 O 7 2 - (aq) + _______ I - (aq)$\rightarrow$_______ Cr 3+ (aq) + _______ I 2 (s)
-Determine the coefficient for the iodide ions.

Question

Quizplus · Accepted Answer

The reaction in question involves the reduction of chromium and the oxidation of iodide ions. In acidic solution, the half-reactions and their balancing would involve adding electrons to balance the charges and adding water and hydrogen ions to balance the oxygen and hydrogen atoms, respectively. The chromium is reduced, meaning it gains electrons, and the iodide is oxidized, meaning it loses electrons. The coefficient for the iodide ions must balance the total change in electrons across both half-reactions. Given that chromium changes its oxidation state from +6 in Cr2O7^2- to +3 in Cr^3+, and each chromium atom gains 3 electrons, for two chromium atoms, a total of 6 electrons are gained. Therefore, the iodide ions must lose 6 electrons (since the total gain and loss of electrons in the reaction must be equal for the reaction to be balanced), which means 6 iodide ions are required to provide these electrons, making the correct answer 6.

Answer the Following Questions That Refer to the Unbalanced Reaction →\rightarrow→

Answer the Following Questions That Refer to the Unbalanced Reaction $\rightarrow$