NEET UG 2012 — Physical Chemistry

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

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

$p_A$ 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

Buffer solutions have constant acidity and alkalinity because

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

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?

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? $$ \mathrm{SO}_3(g) \rightleftharpoons \mathrm{SO}_2(g)+\frac{1}{2} \mathrm{O}_2(g) $$

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

Identify the wrong statement in the following.

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

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 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?

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

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

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

$\mathrm{pH}$ 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

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).

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

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

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

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

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 $\mathrm{CH}_2 \mathrm{Cl}_2=85 \mathrm{~g} / \mathrm{mol}$ ]

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