Question

Cr(NO3)3(aq) + Al(s) ---- Al(NO3)3(aq) + Cr(s) balance the equation

Answer 1

Cr(NO₃)₃(aq) + Al(s) ----> Al(NO₃)₃(aq) + Cr(s)
Stept 1: Identifying which element is oxidized and which element is reduced and then splitting the equation
into two half-reactions:

Reduction: Cr(NO₃)₃(aq) ----> Cr(s)
Oxidatation: Al(s) ----> Al(NO₃)₃(aq)

Step 2: Break reaction into half-reactions by ions and balance the charges: Take out the common ion NO₃^-

Cr⁺³(aq) + 3 e^- ----> Cr(s)
Al(s) ----> Al⁺³ + 3 e^-(aq)
Step 3: Then balance the H or O in the reaction. Since, there are no H and O are present, we no need to do any thing at this step.

Step 4: Scale the reactions to balance electrons of the both equation, so they cancel each other when we add two reactions. In this case, both side we have 3 e^-, so it is already balanced.

Step 5: Now combine the both the reactions reactions and cancel the electrons:
Cr⁺³(aq) + Al(s) ----> Cr(s) + Al⁺³

Step 6: Now, add the common ions NO3- on both side to to balance the equation:
Cr⁺³(aq) + 3 NO₃^- + Al(s) ----> Cr(s)+ Al⁺³ + 3 NO₃^-

Step 7: The balanced equation is:
Cr(NO₃)₃(aq) + Al(s) ----> Al(NO₃)₃(aq) + Cr(s)