Organic Chemistry

Initial rate: $r_1 = k [\text{A}] [\text{B}]$.
When the volume $V$ of the vessel is reduced to $V/4$, the molar concentration ($C = n/V$) of each gas increases by 4 times:

A catalyst increases the speed of a chemical reaction by providing an alternative reaction pathway having a lower activation energy ($E_a$). It does not alter thermodynamic state functions like Gibbs energy change ($\Delta G$), enthalpy of reaction ($\Delta H$), or the equilibrium constant ($K_{\text{eq}}$).

Substances that are repelled by an external magnetic field are diamagnetic (possessing zero unpaired electrons):

• In $\text{Na}_2[\text{CdCl}_4]$, cadmium is in $+2$ oxidation state: $\text{Cd}^{2+} = [\text{Kr}]4d^{10}$ (all electrons paired, diamagnetic).
• In $\text{K}_4[\text{Fe}(\text{CN})_6]$, iron is in $+2$ state: $\text{Fe}^{2+} = [\text{Ar}]3d^6$ low spin $t_{2g}^6 e_g^0$ (all electrons paired, also diamagnetic).
• In $\text{Na}_2[\text{CuCl}_4]$, $\text{Cu}^{2+} = 3d^9$ (1 unpaired electron, paramagnetic).
• In $\text{K}_3[\text{Fe}(\text{CN})_6]$, $\text{Fe}^{3+} = 3d^5$ low spin $t_{2g}^5 e_g^0$ (1 unpaired electron, paramagnetic).

NTA official answer key accepted option 2 (option 3 is also diamagnetic).

Functions and clinical associations of biomolecules:

• Vitamin A (Retinol) deficiency leads to hardening of the cornea called Xerophthalmia and night blindness $\rightarrow$ (II)
• Thiamine (Vitamin $\text{B}_1$) deficiency causes Beri-Beri $\rightarrow$ (III)
• Glucocorticoids regulate carbohydrate metabolism; hyposecretion of adrenal cortex hormones causes Addison's disease $\rightarrow$ (IV)
• Estradiol is the primary female sex hormone that controls the development of secondary sexual characteristics and regulates the menstrual cycle $\rightarrow$ (I)

Correct match: (A)-(II), (B)-(III), (C)-(IV), (D)-(I).