JEE Main 2004 — Physical Chemistry

The limiting molar conductivities $\Lambda^{\circ}$ for $\mathrm{NaCl}, \mathrm{KBr}$ and $\mathrm{KCl}$ are 126,152 and $150 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$ respectively. The $\Lambda^{\circ}$ for $\mathrm{NaBr}$ is

Consider the ground state of $\mathrm{Cr}$ atom $(Z=24)$. The number of electrons with the azimuthal quantum numbers $\mathrm{I}=1$ and 2 are respectively

The standard e.m.f of a cell, involving one electron change is found to be $0.591 \mathrm{~V}$ at $25^{\circ} \mathrm{C}$. The equilibrium constant of the reaction is $\left(\mathrm{F}=96,500 \mathrm{C} \mathrm{mol}^{-1}: \mathrm{R}=8.314 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)$

The molar solubility product is $\mathrm{K}_{\mathrm{sp}}$. ' $\mathrm{s}$ ' is given in terms of $\mathrm{K}_{\mathrm{sp}}$ by the relation

Among the properties (a) reducing (b) oxidising (c) complexing, the set of properties shown by $\mathrm{CN}^{-}$ion towards metal species is

Excess of $\mathrm{KI}$ reacts with $\mathrm{CuSO}_4$ solution and then $\mathrm{Na}_2 \mathrm{~S}_2 \mathrm{O}_3$ solution is added to it. Which of the statements is incorrect for this reaction?

The $\mathrm{E}_{\mathrm{M}^{+3} / \mathrm{M}^{2+}}^{\circ}$ values for $\mathrm{Cr}, \mathrm{Mn}, \mathrm{Fe}$ and Co are $-0.41,+1.57,+0.77$ and $+1.97 \mathrm{~V}$ respectively. For which one of these metals the change in oxidation state form $+2$ to $+3$ is easiest?

To neutralize completely $20 \mathrm{~mL}$ of $0.1 \mathrm{M}$ aqueous solution of phosphorous acid $\left(\mathrm{H}_3 \mathrm{PO}_3\right)$, the volume of $0.1 \mathrm{M}$ aqueous $\mathrm{KOH}$ solution required is

The wavelength of the radiation emitted, when in hydrogen atom electron falls from infinity to stationary state 1 , would be (Rydberg constant $\left.=1.097 \times 10^7 \mathrm{~m}^{-1}\right)$

For the reaction, $\mathrm{CO}(\mathrm{g})+\mathrm{Cl}_2(\mathrm{~g}) \rightleftharpoons \mathrm{COCl}_2(\mathrm{~g})$ the $\frac{\mathrm{K}_{\mathrm{p}}}{\mathrm{K}_{\mathrm{c}}}$ is equal to

An ideal gas expands in volume from $1 \times 10^{-3} \mathrm{~m}^3$ to $1 \times 10^{-2} \mathrm{~m}^3$ at $300 \mathrm{~K}$ against a constant pressure of $1 \times 10^5 \mathrm{Nm}^{-2}$. The work done is

The equilibrium constant for the reaction $\mathrm{N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})$ at temperature $\mathrm{T}$ is $4 \times 10^{-4}$. The value of $\mathrm{Kc}$ for the reaction $\mathrm{NO}(\mathrm{g}) \rightleftharpoons \frac{1}{2} \mathrm{~N}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g})$ at the same temperature is

The rate equation for the reaction $2 \mathrm{~A}+\mathrm{B} \longrightarrow \mathrm{C}$ is found to be: rate $\mathrm{k}[\mathrm{A}][\mathrm{B}]$. The correct statement in relation to this reaction is that the

Which of the following liquid pairs shows a positive deviation from Raoult's law?

The formation of the oxide ion $\mathrm{O}^{2-}(\mathrm{g})$ requires first an exothermic and then an endothermic step as shown below $\mathrm{O}(\mathrm{g})+\mathrm{e}^{-} \mathrm{O}^{-}(\mathrm{g}) \Delta \mathrm{H}^{\circ}=-142 \mathrm{kJmol}^{-1}$ $\mathrm{O}^{-}(\mathrm{g})+\mathrm{e}^{-} \mathrm{O}^{2-}(\mathrm{g}) \Delta \mathrm{H}^{\circ}=844 \mathrm{kJmol}^{-1}$

In hydrogen - oxygen fuel cell, combustion of hydrogen occurs to

What is the equilibrium expression for the reaction $\mathrm{P}_{4(\mathrm{~s})}+5 \mathrm{O}_{2(\mathrm{~g})} \rightleftharpoons \mathrm{P}_4 \mathrm{O}_{10(\mathrm{~s}}$ ?

In first order reaction, the concentration of the reactant decreases from $0.8 \mathrm{M}$ to $0.4 \mathrm{M}$ in 15 minutes. The time taken for the concentration to change from $0.1 \mathrm{M}$ to $0.025 \mathrm{M}$ is

$6.02 \times 10^{20}$ molecules of urea are present in $100 \mathrm{ml}$ of its solution. The concentration of urea solution is

The conjugate base of $\mathrm{H}_2 \mathrm{PO}_4^{-}$is

Consider the following $\mathrm{E}^{\circ}$ values $$ \begin{aligned} & \mathrm{E}_{\mathrm{Fe}^{3+} / \mathrm{Fe}^{2+}}^{\circ}=0.77 \mathrm{~V} \\ & \mathrm{E}_{\mathrm{Sn}^{2+} / \mathrm{Sn}}^{\circ}=-0.14 \mathrm{~V} \end{aligned} $$ Under standard conditions the potential for the reaction $\mathrm{Sn}(\mathrm{s})+2 \mathrm{Fe}^{3+}(\mathrm{aq}) \longrightarrow 2 \mathrm{Fe}^{2+}(\mathrm{aq})+\mathrm{Sn}^{2+}(\mathrm{aq})$ is

Among $\mathrm{Al}_2 \mathrm{O}_3, \mathrm{SiO}_2, \mathrm{P}_2 \mathrm{O}_3$ and $\mathrm{SO}_2$ the correct order of acid strength is

Which of the following sets of quantum numbers is correct for an electron in $4 \mathrm{f}$ orbital?

Which one the following sets of ions represents the collection of isoelectronic species?

In a cell that utilises the reaction $\mathrm{Zn}(\mathrm{s})+2 \mathrm{H}^{+}(\mathrm{aq}) \longrightarrow \mathrm{Zn}^{2+}(\mathrm{aq})+\mathrm{H}_2(\mathrm{~g})$ addition of $\mathrm{H}_2 \mathrm{SO}_4$ to cathode compartment, will

The enthalpies of combustion of carbon and carbon monoxide are $-393.5$ and $-283 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. The enthalpy of formation of carbon monoxide per mole is

The half - life of a radioisotope is four hours. If the initial mass of the isotope was $200 \mathrm{~g}$, the mass remaining after 24 hours undecayed is