- A) \( {[MnBr}_4]^{2-} \): The \( {Mn}^{2+} \) ion has an \( 3d^5 \) configuration, leading to an \( sp^3 \) hybridization with a diamagnetic behavior due to the pairing of electrons. Hence, it corresponds to (III).
- B) \( {[FeF}_6]^{3-} \): The \( {Fe}^{3+} \) ion has a \( 3d^5 \) configuration, resulting in \( sp^2d^2 \) hybridization with paramagnetic behavior. Hence, it corresponds to (II).
- C) \( {[Co(C}_2{O}_4)_3]^{3-} \): The \( {Co}^{3+} \) ion leads to a \( 3d^6 \) configuration, requiring \( d^2sp^3 \) hybridization with diamagnetic behavior. Hence, it corresponds to (I).
- D) \( [Ni(CO)_4] \): The \( {Ni}^{2+} \) ion has a \( 3d^8 \) configuration with \( sp^3 \) hybridization and paramagnetic behavior. Hence, it corresponds to (IV). Thus, the correct matching is (A)-(III), (B)-(II), (C)-(I), (D)-(IV).
Consider the following two reactions A and B: 
The numerical value of [molar mass of $x$ + molar mass of $y$] is ___.
Which one of the following graphs accurately represents the plot of partial pressure of CS₂ vs its mole fraction in a mixture of acetone and CS₂ at constant temperature?

Consider the following reaction sequence: 
Given: Compound (x) has percentage composition \(76.6%\ \text{C}\), \(6.38%\ \text{H}\) and vapour density \(=47\). Compound (y) develops a characteristic colour with neutral \(\mathrm{FeCl_3}\) solution. Identify the {INCORRECT statement.}
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 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