How many electrons are required to balance the following half-reaction?
Au + 4 Cl- ⟶ AuCl4-
A. 2 electrons on the products side
B. 2 electrons on the reactants side
C. 3 electrons on the products side
D. 3 electrons on the reactants side
Please help ASAP!!! :(
Well, well, it seems we have a balancing act here! Let me put on my juggling shoes and help you out.
In the given half-reaction, we have Au (+1 charge) reacting with 4 Cl- (-1 charge each) to form AuCl4- (-1 charge).
To balance the charges and make sure the reaction is jolly good, we need to have the same charge on both sides.
Since Au loses a +1 charge and Cl- doesn't change its charge, we need 1 extra negative charge on the left side to balance it out. And because 4 Cl- ions are involved, we'll need a total of 4 negative charges on the reactants side.
So the answer is B. 2 electrons on the reactants side. They'll swoop in like tiny circus performers to balance the charges and bring harmony to the reaction. Keep up the great work, chemistry maestro!
To determine the number of electrons required to balance the given half-reaction, you need to follow these steps:
1. Identify the element that undergoes a change in oxidation number. In this case, it is Au (gold), which changes from a neutral atom (oxidation state 0) to Au3+.
2. Write the half-reaction for the oxidation step. In this case, Au goes from 0 to Au3+, so the half-reaction is: Au ⟶ Au3+.
3. Determine the number of electrons involved in the oxidation step by comparing the changes in oxidation numbers. 0 → 3+ represents a loss of electrons, so the number of electrons lost is equal to the increase in oxidation number, which is 3. Therefore, 3 electrons are involved in the oxidation step.
4. Determine the number of electrons required for the reduction step by balancing the charges. In the balanced compound, AuCl4-, the overall charge is -1. Since each chloride ion (Cl-) carries a charge of -1, then there are four chloride ions involved in the reduction step. To balance the charge, 4 electrons are needed to reduce Au3+ to Au.
Therefore, the correct answer is:
D. 3 electrons on the reactants side.
Three electrons are needed on the reactants side to balance the oxidation step, Au ⟶ Au3+.
It is worth noting that there are also four chloride ions on the reactants side, but since the question specifically asks about the number of electrons, the correct answer is D.
Au on the left has an oxidation state of 0
Au on the right has a oxidation state of 3+
So change in electrons must be .........