JEE Main 2003 — Physical Chemistry

If liquids $\mathrm{A}$ and $\mathrm{B}$ form an ideal solution

The half-life of a radioactive isotope is three hours. If the initial mass of the isotope were $256 \mathrm{~g}$, the mass of it remaining undecayed after 18 hours would be

If at $298 \mathrm{~K}$ the bond energies of $\mathrm{C}-\mathrm{H}, \mathrm{C}-\mathrm{C}, \mathrm{C}=\mathrm{C}$ and $\mathrm{H}-\mathrm{H}$ bonds are respectively $414,347,615$ and $435 \mathrm{~kJ}$ $\mathrm{mol}^{-1}$, the value of enthalpy change for the reaction $\mathrm{H}_2 \mathrm{C}=\mathrm{CH}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{H}_3 \mathrm{C}-\mathrm{CH}_3(\mathrm{~g})$ at $298 \mathrm{~K}$ will be

For a cell reaction involving a two-electron change, the standard e.m.f. of the cell is found to be $0.295 \mathrm{~V}$ at $25^{\circ} \mathrm{C}$. The equilibrium constant of the reaction at $25^{\circ} \mathrm{C}$ will be

Which of the following could act as apropellant for rockets?

The enthalpy change for a reaction does not depend upon

In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen

Standard reduction electrode potentials of three metals A,B\&C are respectively $+0.5 \mathrm{~V},-3.0 \mathrm{~V} \&-1.2 \mathrm{~V}$. The reducing, powers of these metals are

Which one of the following statements is not true?

In an irreversible process taking place at constant $\mathrm{T}$ and $\mathrm{P}$ and in which only pressure-volume work is being done, the change in Gibbs free energy (dG) and change in entropy (dS), satisfy the criteria

A pressure cooker reduces cooking time for food because

The rate law for a reaction between the substances $\mathrm{A}$ and $\mathrm{B}$ is given by Rate $=\mathrm{k}[\mathrm{A}]^{\mathrm{n}}[\mathrm{B}]^{\mathrm{m}}$ On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as

Which one of the following groupings represents a collection of isoelectronic species? (At. nos,: 55, Br:35)

$25 \mathrm{ml}$ of a solution of barrium hydroxide on titration with a $0.1$ molar solution of hydrochloric acid gave a litre value of $35 \mathrm{ml}$. The molarity of barium hydroxide solution was

When rain is accompanied by a thunderstorm, the collected rain water will have a $\mathrm{pH}$ value

Consider the reaction equilibrium $2 \mathrm{SO}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{SO}_3(\mathrm{~g}) ; \Delta \mathrm{H}^0=-198 \mathrm{~kJ}$. On the basis of Le Chatelier's principle, the condition favourable for the forward reaction is

The orbital angular momentum for an electron revolving in an orbit is given by $\sqrt{l(l+1)} \cdot \frac{\mathrm{h}}{2 \pi}$. This momentum for an s-electron will be given by

In a $0.2$ molal aqueous solution of a weak acid $\mathrm{HX}$ the degree of ionization is $0.3$. Taking $\mathrm{k}_{\mathrm{f}}$ for water as $1.85$, the freezing point of the solution will be nearest to

The solubility in water of a sparingly soluble salt $\mathrm{AB}$ is $1.0 \times 10^{-5} \mathrm{~mol} \mathrm{~L}^{-1}$. Its solubility product number will be

The internal energy change when a system goes from state $\mathrm{A}$ to $\mathrm{B}$ is $40 \mathrm{~kJ} / \mathrm{mole}$. If the system goes from $\mathrm{A}$ to $\mathrm{B}$ by a reversible path and retums to state $\mathrm{A}$ by an irreversible path what would be the net change in internalenergy?

In respect of the equation $\mathrm{k}=\mathrm{Ae}^{-\mathrm{E}_{\mathrm{o}} / \mathrm{RT}}$ in chemical kinetics, which one of the following statements is correct?

What volume of hydrogen gas, at $273 \mathrm{~K}$ and $1 \mathrm{~atm}$, pressure will be consumed in obtaining $21.6 \mathrm{~g}$ of elemental boron (atomic mass $=10.8$ ) from the reducti on of boron trichloride by hydrogen?

For the reaction system: $2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{NO}_2(\mathrm{~g})$ volume is suddenly reduce to half its value by increasing the pressure on it. If the reaction is of first order with respect to $\mathrm{O}_2$ and second order with respect to $\mathrm{NO}$, the rate of reaction will

When during electrolysis of a solution of $\mathrm{AgNO}_3 9650$ coulombs of charge pass through the electroplating bath, the mass of silver deposited on the cathode will be

For the redox reaction $\mathrm{Zn}(\mathrm{s})+\mathrm{Cu}^{2+}(0.1 \mathrm{M}) \rightarrow \mathrm{Zn}^{2+}(1 \mathrm{M})+\mathrm{Cu}(\mathrm{s})$ taking place in a cell, $\mathrm{E}_{\text {cell }}^0$ is $1.10$ volt. $\mathrm{E}^{\circ}$ for the cell will be $\left(2.303 \frac{\mathrm{RT}}{\mathrm{F}}=0.0591\right)$

The de Broglie wavelength of a tennis ball of mass $60 \mathrm{~g}$ moving with a velocity of 10 metres per second is approximately

The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $\mathrm{K}_{\mathrm{c}}$ is

For the reaction equilibrium $\mathrm{N}_2 \mathrm{O}_4(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}_2(\mathrm{~g})$ the concentrations of $\mathrm{N}_2 \mathrm{O}_4$ and $\mathrm{NO}_2$ at equilibrium are $4.8 \times 10^{-2}$ and $1.2 \times 10^{-2} \mathrm{~mol} \mathrm{~L}^{-1}$ respectively. The value of $\mathrm{K}_{\mathrm{c}}$ for the reaction is