Answer to Question 1
A Although perfectly competitive firms produce at the minimum average total cost, that result does not mean that the firm's total product is at its maximum. Each firm could produce more, albeit at a higher average total cost.
Answer to Question 2
The deadweight loss is the decrease in total surplus that results from an inefficient level of production. This is the decrease in consumer surplus plus the decrease in producer surplus that occurs when the market either overproduces or underproduces relative to the efficient quantity.