Answer
The intermediate is on the image below:
Work Step by Step
1. Analyze the arrows.
First arrow (Left):
- Tail: It is breaking a "C-O" bond...
- Head: to give the electrons pair to an oxygen.
Second arrow (Right):
- Tail: It is taking 2 electrons from an oxygen...
- Head: to form a bond between this oxygen and a carbon.
2. Now, let's find the formal charges:
The left oxygen had neutral charge, then it lost a bond (+1), and gained 2 electrons (-2) = -1 formal charge.
The other oxygen had (-1) as a charge, then it lost 2 electrons (+2), and formed a bond (-1) = Neutral formal charge.
