Remember the truth tables for basic logical operations (and, or, not, implication). A contradiction is always false, and a tautology is always true
For \( S_1 : (p \rightarrow q) \land (p \land \sim q) \), the truth table is:
| \( p \) | \( q \) | \( p \rightarrow q \) | \( p \land \sim q \) | \( S_1 \) |
|---|---|---|---|---|
| T | T | T | F | F |
| T | F | F | T | F |
| F | T | T | F | F |
| F | F | T | F | F |
From the truth table, \( S_1 \) is a Contradiction, as \( S_1 \) is always false.
For \( S_2 : (\sim p \land q) \lor (p \land \sim q) \), the truth table is:
| \( p \) | \( q \) | \( p \land q \) | \( \sim p \land q \) | \( p \land \sim q \) | \( (\sim p \land q) \lor (p \land \sim q) \) | \( S_2 \) |
|---|---|---|---|---|---|---|
| T | T | T | F | F | F | F |
| T | F | F | F | T | T | T |
| F | T | F | T | F | T | T |
| F | F | F | F | F | F | F |
From the truth table, \( S_2 \) is a Tautology, as \( S_2 \) is always true.
Hence:
\( S_1 \) is Contradiction, and \( S_2 \) is Tautology.
In the following \(p\text{–}V\) diagram, the equation of state along the curved path is given by \[ (V-2)^2 = 4ap, \] where \(a\) is a constant. The total work done in the closed path is: 
Let \( ABC \) be a triangle. Consider four points \( p_1, p_2, p_3, p_4 \) on the side \( AB \), five points \( p_5, p_6, p_7, p_8, p_9 \) on the side \( BC \), and four points \( p_{10}, p_{11}, p_{12}, p_{13} \) on the side \( AC \). None of these points is a vertex of the triangle \( ABC \). Then the total number of pentagons that can be formed by taking all the vertices from the points \( p_1, p_2, \ldots, p_{13} \) is ___________.
Consider the following two reactions A and B: 
The numerical value of [molar mass of $x$ + molar mass of $y$] is ___.