Write the half reactions and the balanced
equation for the galvanic cell
Hg(ℓ)| Hg2(+2)(aq)|| MnO(−4)(aq), Mn2 (aq), H(+)(aq)| Pt(s).
What is the smallest possible integer coefficient of Mn(2+)(aq) in the combined balanced equation?
I'm struggling too Allison. Its a real Debbie downer that we can't find this quest answer anywhere
To find the half reactions and the balanced equation for the given galvanic cell, we need to follow a few steps:
Step 1: Identify the oxidation and reduction half-reactions.
In this case, we have the following half-reactions:
Oxidation Half-reaction: Hg(ℓ) → Hg2(+2)(aq)
Reduction Half-reaction: MnO(−4)(aq) → Mn2+(aq)
Step 2: Balance the half-reactions individually.
Balancing the oxidation half-reaction (Hg(ℓ) → Hg2(+2)(aq)):
Since mercury (Hg) goes from a neutral atom to a +2 ion, we need to add 2 electrons (e^-) to the left side of the equation to balance the charges:
Hg(ℓ) → Hg2(+2)(aq) + 2e^-
Balancing the reduction half-reaction (MnO(−4)(aq) → Mn2+(aq)):
First, let's break down the reaction into two half-reactions, one for the reduction of Mn and another for the oxidation of oxygen:
Reduction of Mn:
MnO(−4)(aq) → Mn2+(aq)
Balancing the Mn atoms:
We need to add 4 hydrogen ions (H+) to the right side to balance the Mn atoms:
MnO(−4)(aq) → Mn2+(aq) + 4H+(aq)
Balancing the Oxygen (O) atoms:
We need to add 4 water molecules (H2O) to the left side to balance the oxygen atoms:
MnO(−4)(aq) + 4H2O(l) → Mn2+(aq) + 4H+(aq)
Finally, we need to balance the charges by adding 4 electrons (e^-) to the left side:
MnO(−4)(aq) + 4H2O(l) + 4e^- → Mn2+(aq) + 4H+(aq)
Step 3: Combine the two half-reactions to form the overall balanced equation.
Since both half-reactions involve the transfer of electrons, we can add them together. However, before adding them, we need to multiply each half-reaction by factors to equalize the number of electrons:
Multiplying the oxidation half-reaction by 2:
2Hg(ℓ) → 2Hg2(+2)(aq) + 4e^-
The electrons are now equal in both half-reactions, so we can add them together:
2Hg(ℓ) + MnO(−4)(aq) + 4H2O(l) + 4e^- → 2Hg2(+2)(aq) + Mn2+(aq) + 4H+(aq)
Step 4: Simplify and balance the final equation.
To simplify the balanced equation, we can combine like terms:
2Hg(ℓ) + MnO(−4)(aq) + 4H2O(l) → 2Hg2(+2)(aq) + Mn2+(aq) + 4H+(aq)
The smallest possible integer coefficient of Mn2+(aq) in the combined balanced equation is 1.