"John" wrote:

The purpose of having grounding pin on AC outlet is to ground metalic
surfaces of appliances so that there can be no voltage to hurt anyone even
if there is a leak. Right?

Right.

If an AC outlet has the ground and neutral reversed, would it cause any
problem?

If the neutral is shared with another outlet, there is the very real
possibility of voltage being on it.

If an AC outlet has no grounding wire (old house) and instead the ground
prong is connected to the neutral, would that cause any problem?

Yes, then the metal surfaces of the appliance would be subject to
voltage.

Is neutral connected to ground at the circult breaker panel?

Yes, but that does not mean they are interchangeable in usage at the
outlet end. It is to insure that the breakers trip if the hot line is
shorted out to ground and not just the other side of the power line.



--
If I had something witty to say, this is where I'd say it.