Question

which post should be disconnected second when removing a battery?
depends on battery construction
positive
either - no differnece
negative

Explanation:

When removing a battery, it is a safety - related procedure. The general rule is to disconnect the negative terminal first. When reconnecting, the positive is connected first. But when disconnecting, after the negative (first), the positive (second) is disconnected. This is to prevent electrical arcs and short - circuits. If the positive was disconnected first, there could be a risk of accidental contact with the vehicle's metal parts (which are usually connected to the negative terminal via the chassis) causing a spark.

Answer:

Positive