| List-I | Polymer | List-II | Type/ Class |
| (A) | Nylon-2-Nylon-6 | (I) | Thermosetting polymer |
| (B) | Buna-N | (II) | Biodegradable polymer |
| (C) | Urea-formaldehyde | (III) | Synthetic rubber resin |
| (D) | Dacron | (IV) | Polyester |
Understanding the properties and applications of polymers helps in correctly identifying their types. For example, biodegradable polymers like Nylon-2-Nylon 6 decompose naturally, while synthetic rubbers like Buna-N are used for their elasticity
The correct match is:
Final Answer: (2)

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 ___.
Consider an A.P. $a_1,a_2,\ldots,a_n$; $a_1>0$. If $a_2-a_1=-\dfrac{3}{4}$, $a_n=\dfrac{1}{4}a_1$, and \[ \sum_{i=1}^{n} a_i=\frac{525}{2}, \] then $\sum_{i=1}^{17} a_i$ is equal to