Which of the following is an open statement?

The correct logical equivalences from the following are:
$(I)$ $p \to (q \to r) \equiv (p \land q) \to r$
$(II)$ $(p \to q) \to r \equiv p \to (q \lor r)$
$(III)$ $(p \to q) \to r \equiv (p \to r) \land (\sim q \to r)$
$(IV)$ $p \to (q \to r) \equiv q \to (p \to r)$

Which of the following quantified statements is true?

The dual of the statement pattern $(p \land \sim q) \to (q \land \sim p)$ is equivalent to

If $P$ and $Q$ are two statements,then which of the following compound statements is a tautology?

The negation of the statement "The triangle is an equilateral or isosceles triangle and the triangle is not isosceles and it is right angled" is