3. you arrive at an intersection with traffic lights that are not working because of a power outage. what do you do?

I would wait to the police of traffic guy arrive, just to prevent any crashes.

Come to a complete stop and act as if it's a red light

You don't actually need to know the molecular formula for lactic acid in order to solve this problem.
You are told that lactic acid has one acidic proton, which means that you can represent it as
HA
.
So, you know that the pH of a solution that is
0.10 M
lactic acid is equal to
2.44
. As you know, a solution's pH is simply a measure of the concentration of hydronium ions,
H
3
O