The false statement in the following is
p∧(~p) is contradiction
(p⇒q)⇔(~q⇒∼p) is a contradiction
~(~p)⇔p is a tautology
p∨(~p)⇔ is a tautology
p⇒q is a tautology ~q⇒∼p
∴(p⇒q)⇔(~q⇒∼p) s a tautology but not a contraction