Which of the following is an open statement

Negation of the compound proposition : If the examination is difficult, then I shall pass if I study hard

Which one of the following, statements is not a tautology

Consider

Statement $-1 :$$\left( {p \wedge \sim q} \right) \wedge \left( { \sim p \wedge q} \right)$ is a fallacy.

Statement $-2 :$$(p \rightarrow q) \leftrightarrow ( \sim q \rightarrow   \sim  p )$  is a tautology.

Which of the following is a tautology?