NEET UG 2012 — Physical Chemistry

Four successive members of the first series of the transition metals are listed below. For which one of them the standard potential $\left(E_{M^{2+} / M}^{\circ}\right)$ value has a positive sign?

Molar conductivities $\left(\Lambda_m^{\circ}\right)$ at infinite dilution of $\mathrm{NaCl}, \mathrm{HCl}$ and $\mathrm{CH}_3 \mathrm{COONa}$ are 126.4, 425.9 and $91.0 \mathrm{~S} \mathrm{~cm} \mathrm{cmol}^{-1}$ respectively. $\Lambda^{\circ}{ }_m$ for $\mathrm{CH}_3 \mathrm{COOH}$ will be

A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the reaction which element undergoes maximum change in the oxidation number?

$p_A$ and $p_B$ are the vapour pressure of pure liquid components, $A$ and $B$, respectively of an ideal binary solution. If $x_A$ represents the mole fraction of component $A$, the total pressure of the solution will be

In a zero order reaction for every $10^{\circ}$ rise of temperature, the rate is doubled. If the temperature is increased from $10^{\circ} \mathrm{C}$ to $100^{\circ} \mathrm{C}$, the rate of the reaction will become

In which of the following compounds, nitrogen exhibits highest oxidation state?

In a reaction, $A+B \rightarrow$ Product, rate is doubled when the concentration of $B$ is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants $(A$ and $B$ ) are doubled. Rate law for the reaction can be written as

Standard enthalpy of vaporisation $\Delta_{\mathrm{vap}} H^{\mathrm{s}}$ for water at $100^{\circ} \mathrm{C}$ is $40.66 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The internal energy of vaporisation of water at $100^{\circ} \mathrm{C}$ (in $\left.\mathrm{kJ} \mathrm{mol}^{-1}\right)$ is (Assume water vapour to behave like an ideal gas).

In which of the following reactions, standard reaction entropy changes $\left(\Delta S^{\circ}\right)$ is positive and standard Gibb's energy change $\left(\Delta G^{\circ}\right)$ decreases sharply with increasing temperature?

The correct set of four quantum numbers for the valence electron of rubidium atom $(Z=37)$ is

Activation energy $\left(E_a\right)$ and rate constants $\left(k_1\right.$ and $\left.k_2\right)$ of a chemical reaction at two different temperatures $\left(T_1\right.$ and $\left.T_2\right)$ are related by

Which of the following compounds can be used as antifreeze in automobile radiators?

Vapour pressure of chloroform $\left(\mathrm{CHCl}_3\right)$ and dichloromethane $\left(\mathrm{CH}_2 \mathrm{Cl}_2\right)$ at $25^{\circ} \mathrm{C}$ are $200 \mathrm{~mm} \mathrm{Hg}$ and $415 \mathrm{~mm} \mathrm{Hg}$ respectively. Vapour pressure of the solution obtained by mixing $25.5 \mathrm{~g}$ of $\mathrm{CHCl}_3$ and $4 \mathrm{O} \mathrm{g}$ of $\mathrm{CH}_2 \mathrm{Cl}_2$ at the same temperature will be: [Molecular mass of $\mathrm{CHCl}_3=119.5 \mathrm{~g} / \mathrm{mol}$ and molecular mass of $\mathrm{CH}_2 \mathrm{Cl}_2=85 \mathrm{~g} / \mathrm{mol}$ ]

Identify the wrong statement in the following.

The orbital angular momentum of a p-electron is given as

Maximum number of electrons in a subshell with $l=3$ and $n=4$ is

Buffer solutions have constant acidity and alkalinity because

Given that the equilibrium constant for the reaction, $$ 2 \mathrm{SO}_2(g)+\mathrm{O}_2(g) \rightleftharpoons 2 \mathrm{SO}_3(g) $$ has a value of 278 at a particular temperature. What is the value of the equilibrium constant for the following reaction at the same temperature? $$ \mathrm{SO}_3(g) \rightleftharpoons \mathrm{SO}_2(g)+\frac{1}{2} \mathrm{O}_2(g) $$

The Gibbs' energy for the decomposition of $\mathrm{Al}_2 \mathrm{O}_3$ at $500^{\circ} \mathrm{C}$ is as follows $$ \begin{gathered} \frac{2}{3} \mathrm{Al}_2 \mathrm{O}_3 \longrightarrow \frac{4}{3} \mathrm{Al}+\mathrm{O}_2 ; \\ \Delta_r G=+960 \mathrm{~kJ} \mathrm{~mol}^{-1} \end{gathered} $$ The potential difference needed for the electrolytic reduction of aluminium oxide $\left(\mathrm{Al}_2 \mathrm{O}_3\right)$ at $500^{\circ} \mathrm{C}$ is at least

$\mathrm{pH}$ of a saturated solution of $\mathrm{Ba}(\mathrm{OH})_2$ is 12. The value of solubility product $K_{\text {sp }}$ of $\mathrm{Ba}(\mathrm{OH})_2$ is

The enthalpy of fusion of water is $1.435 \mathrm{kcal} / \mathrm{mol}$. The molar entropy change for the melting of ice at $0^{\circ} \mathrm{C}$ is

Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest $\mathrm{pH}$ value?

Standard reduction potentials of the half reactions are given below $$ \begin{array}{ll} \mathrm{F}_2(g)+2 e^{-} \longrightarrow 2 \mathrm{~F}^{-}(a q) ; & E^{\circ}=+2.85 \mathrm{~V} \\ \mathrm{Cl}_2(g)+2 e^{-} \longrightarrow 2 \mathrm{Cl}^{-}(a q) ; & E^{\circ}=+1.36 \mathrm{~V} \\ \mathrm{Br}_2(l)+2 e^{-} \longrightarrow 2 \mathrm{Br}^{-}(a q) ; & E^{\circ}=+1.06 \mathrm{~V} \\ \mathrm{I}_2(s)+2 e^{-} \longrightarrow 2 \mathrm{I}^{-}(a q) ; & E^{\circ}=+0.53 \mathrm{~V} \end{array} $$ The strongest oxidising and reducing agents respectively are

Given the reaction between two gases represented by $A_2$ and $B_2$ to give the compound $A B(g)$. $$ A_2(g)+B_2(g) \rightleftharpoons 2 A B(g) $$ At equilibrium, the concentration of $A_2=3.0 \times 10^{-3} \mathrm{M}$ of $B_2=4.2 \times 10^{-3} \mathrm{M}$ of $A B=2.8 \times 10^{-3} \mathrm{M}$ If the reaction takes place in a sealed vessel at $527^{\circ} \mathrm{C}$, then the value of $K_c$ will be

Limiting molar conductivity of $\mathrm{NH}_4 \mathrm{OH~} \left( \text{i.e., } \stackrel{\circ}{\Lambda}_{m\left(\mathrm{NH}_4 \mathrm{OH}\right)}\right)$ is equal to