JEE Main 2005 — Physical Chemistry

For the reaction $$ \begin{aligned} & 2 \mathrm{NO}_{2(\mathrm{~g})} \rightleftharpoons 2 \mathrm{NO}_{(\mathrm{g})}+\mathrm{O}_{2(\mathrm{~g})} \text {, } \\ & \left(\mathrm{K}_{\mathrm{c}}=1.8 \times 10^{-6} \text {at } 184 \mathrm{C}\right) \\ & (\mathrm{R}=0.0831 \mathrm{~kJ} /(\mathrm{mol} . \mathrm{K}) \end{aligned} $$ When $\mathrm{K}_{\mathrm{p}}$ and $\mathrm{K}_{\mathrm{c}}$ are compared at $184^{\circ} \mathrm{C}$, it is found that

 Calculate $\wedge_{H O A c}^{\infty}$ Using appropriate molar conductances of the electrolytes listed above at infinite dilution in $\mathrm{H}_2 \mathrm{O}$ at $25^{\circ} \mathrm{C}$

Of the following sets which one does NOT contain isoelectronic species?

In a multi – electron atom, which of the following orbitals described by the three quantum numbers will have the same energy in the absence of magnetic acid and electric fields? (a) $n=1, l=0, m=0$ (b) $n=2, l=0, m=0$ (c) $n=2, l=1, m=1$ (d) $n=3, l=2, m=1$ (e) $n=3, l=2, m=0$

If we consider that $\frac{1}{6}$, in place of $\frac{1}{12}$; mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Consider the reaction: $\mathrm{N}_2+3 \mathrm{H}_2 \longrightarrow 2 \mathrm{NH}_3$ carried out at constant temperature and pressure. If $\Delta \mathrm{H}$ and $\Delta \mathrm{U}$ are the enthalpy and internal energy changes for the reaction, which of the following expressions is true?

The exothermic formation of $\mathrm{ClF}_3$ is represented by the equation: $$ \mathrm{Cl}_{2(g)}+3 \mathrm{~F}_{2(g)} \rightleftharpoons 2 \mathrm{ClF}_{3(g)} ; \Delta \mathrm{r} \mathrm{H}=-329 \mathrm{~kJ} $$ Which of the following will increase the quantity of $\mathrm{ClF}_3$ in an equilibrium mixture of $\mathrm{Cl}_2, \mathrm{~F}_2$ and $\mathrm{ClF}_3$ ?

A reaction involving two different reactants can never be

The solubility product of a salt having general formula $M X_2$, in water is: $4 \times 10^{-12}$. The concentration of $\mathrm{M}^{2+}$ ions in the aqueous solution of the salt is

Two solutions of a substance (non electrolyte) are mixed in the following manner. 480 ml of 1.5 M first solution + 520 mL of 1.2 M second solution. What is the molarity of the final mixture?

Which of the following statements in relation to the hydrogen atom is correct?

What is the conjugate base of $\mathrm{OH}^{-} ?$

Equimolar solutions in the same solvent have

The highest electrical conductivity of the following aqueous solutions is of

Calomel $\left(\mathrm{Hg}_2 \mathrm{Cl}_2\right)$ on reaction with ammonium hydroxide gives

If $\alpha$ is the degree of dissociation of $\mathrm{Na}_2 \mathrm{SO}_4$, the vant Hoff's factor (i) used for calculating the molecular mass is

If the bond dissociation energies of $X Y, X_2$ and $Y_2$ (all diatomic molecules) are in the ratio of 1:1:0.5 and $\Delta_t \mathrm{H}$ for the formation of $X Y$ is $-200 \mathrm{~kJ} \mathrm{~mole}^{-1}$. The bond dissociation energy of $\mathrm{X}_2$ will be

An organic compound having molecular mass 60 is found to contain $\mathrm{C}=20 \%, \mathrm{H}=$ $6.67 \%$ and $\mathrm{N}=46.67 \%$ while rest is oxygen. On heating it gives $\mathrm{NH}_3$ alongwith a solid residue. The solid residue give violet colour with alkaline copper sulphate solution. The compound is

Hydrogen ion concentration in mol / L in a solution of pH = 5.4 will be

An amount of solid $\mathrm{NH}_4 \mathrm{HS}$ is placed in a flask already containing ammonia gas at a certain temperature and $0.50 \mathrm{~atm}$. Pressure. Ammonium hydrogen sulphide decomposes to yield $\mathrm{NH}_3$ and $\mathrm{H}_2 \mathrm{~S}$ gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to $0.84 \mathrm{~atm}$. The equilibrium constant for $\mathrm{NH}_4 \mathrm{HS}$ decomposition at this temperature is

$\mathrm{t}_{1 / 4}$ can be taken as the time taken for the concentration of a reactant to drop to $\frac{3}{4}$ of its initial value. If the rate constant for a first order reaction is $\mathrm{K}$, the $\mathrm{t}_{1 / 4}$ can be written as

For a spontaneous reaction the $\Delta \mathrm{G}$, equilibrium constant $(\mathrm{K})$ and $\mathrm{E}_{\mathrm{cell}}^{\circ}$ will be respectively

Consider an endothermic reaction, $X \longrightarrow Y$ with the activation energies $E_b$ and $E_f$ for the backward and forward reactions, respectively. In general

Aluminium oxide may be electrolysed at $1000^{\circ} \mathrm{C}$ to furnish aluminium metal (Atomic mass $=27$ amu; 1 Faraday $=96,500$ Coulombs). The cathode reaction is $\mathrm{Al}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Al}^{\circ}$ To prepare $5.12 \mathrm{~kg}$ of aluminium metal by this method would require

A schematic plot of ln $\mathrm{K}_{\text {eq }}$ versus inverse of temperature for a reaction is shown below  The reaction must be