During an electrochemical investigation performed in acidic solution
CHEMISTRY · Multi-part · A Level · Chemistry · Oxidation, reduction and redox reactions · Oxidation, reduction and redox reactions
Problem
During an electrochemical investigation performed in acidic solution, the following two skeletal half-reactions were detected.
Half-reaction A: Cu2++e−→Cu+
Half-reaction B: Cr3+→Cr6++3e−
Neither the scaling of electrons nor the final overall reaction has been completed.
(1) Part 1: (a) For each half-reaction, identify whether the process is an oxidation or a reduction and justify your choice by citing the relevant change in oxidation number for the metal involved.
(2) Part 2: (b) Describe, in a logically ordered sequence, the complete set of steps required to combine Half-reactions A and B into a single balanced ionic equation in acidic solution. Your description must explicitly reference how mass balance, charge balance, and electron balance are simultaneously satisfied.
(3) Part 3: (c) If the same redox chemistry were instead carried out in basic solution, explain the additional procedural modifications you would make to the steps outlined in part (b) to obtain a properly balanced equation for basic medium.