Physical Chemistry PYQ — Page 19

Standard free energies of formation (in $\mathrm{kJ} / \mathrm{mol}$ ) at $298 \mathrm{~K}$ are $-237.2,-394.4$ and -8.2 for $\mathrm{H}_2 \mathrm{O}(\mathrm{l}), \mathrm{CO}_2(\mathrm{~g})$ and pentane $(\mathrm{g})$ respectively. The value of $\mathrm{E}_{\text {cell }}^{\circ}$ for the pentaneoxygen fuel cell is

If the lattice parameter for a crystalline structure is $3.6 \%$, then the atomic radius in fcc crystal is

If ' $a$ ' stands for the edge length of the cubic systems : simple cubic, body centred cubic and face centred cubic, then the ratio of radii of the spheres in these systems will be respectively,

Bond dissociation enthalpy of $\mathrm{H}_2, \mathrm{Cl}_2$ and $\mathrm{HCl}$ Enthalpy of formation of $\mathrm{HCl}$ is

Volume occupied by one molecule of water (density $\left.=1 \mathrm{~g} \mathrm{~cm}^{-3}\right)$ is

The rate constants $k_1$ and $k_2$ for two different reactions are $10^{16} \cdot e^{-2000 / T}$ and $10^{15} \cdot e^{-1000 / T}$, respectively. The temperature at which $k_1=k_2$ is

Kohlrausch's law states that at

The measurement of the electron position is associated with an uncertainty in momentum, which is equal to $1 \times 10^{-18} \mathrm{~g} \mathrm{~cm} \mathrm{~s}^{-1}$. The uncertainty in electron velocity is, (mass of an electron is $9 \times 10^{-28} \mathrm{~g}$ )

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave $\mathrm{C}, 38.71 \%$ and $\mathrm{H}, 9.67 \%$. The empirical formula of the compound would be

On the basis of the following $\mathrm{E}^{\circ}$ values, the strongest oxidizing agent is $$ \begin{array}{ll} {\left[\mathrm{Fe}(\mathrm{CN})_\theta\right]^{4-} \rightarrow\left[\mathrm{Fe}(\mathrm{CN})_\theta\right]^{3-}+\mathrm{e}^{-1} ;} & \mathrm{E}^0=-0.35 \mathrm{~V} \\ \mathrm{Fe}^{2+} \rightarrow \mathrm{Fe}^{3+}+\mathrm{e}^{-1} ; & \mathrm{E}^0=-0.77 \mathrm{~V} \end{array} $$

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, $38.71 \%$ and $\mathrm{H}, 9.67 \%$. The empirical formula of the compound would be

The values of $K_{P 1}$ and $K_{\mathrm{P} 2}$ for the reactions $$ \begin{aligned} & X \rightleftharpoons Y+Z . \\ & A \rightleftharpoons 2 B . . \end{aligned} $$ are in ratio of 9:1. If degree of dissociation of $X$ and $\mathrm{A}$ be equal, then total pressure at equilibrium (1) and (2) are in the ratio

How many moles of lead (II) chloride will be formed from a reaction between $6.5 \mathrm{~g}$ of $\mathrm{PbO}$ and $3.2 \mathrm{~g}$ of $\mathrm{HCl}$ ?

Number of moles of $\mathrm{MnO}_4^{-}$required to oxidize one mole of ferrous oxalate completely in acidic medium will be

Number of moles of $\mathrm{MnO}_4^{-}$required to oxidise one mole of ferrous oxalate completely in acidic medium will be

The measurement of the electron position is associated with an uncertainty in momentum, which is equal to $1 \times 10^{-18} \mathrm{~g} \mathrm{~cm} \mathrm{~s}^{-1}$. The uncertainty in electron velocity is, (mass of an electron is $9 \times 10^{-28} \mathrm{~g}$ )

If uncertainty in position and momentum are equal, then uncertainty in velocity is

Which of the following are not state functions? (I) $q+W$ (II) $q$ (III) $W$ (IV) $H-T S$

Percentage of free space in a body centred cubic unit cell is

For the gas phase reaction, $\mathrm{PCl}_5(\mathrm{~g}) \rightleftharpoons \mathrm{PCl}_3(\mathrm{~g})+\mathrm{Cl}_2(\mathrm{~g})$ Which of the following conditions is correct?

The relative reactivities of acyl compounds towards nucleophilic substitution are in the order of

The bromination of acetone that occurs in acid solution is represented by this equation $\mathrm{CH}_3 \mathrm{COCH}_3(\mathrm{aq})+\mathrm{Br}_2(\mathrm{aq}) \rightarrow \mathrm{CH}_3 \mathrm{COCH}_2 \mathrm{Br}(\mathrm{aq})+\mathrm{H}^{+}(\mathrm{aq})+\mathrm{Br}^{-}(\mathrm{aq})$ These kinetic data were obtained for given reaction concentrations Initial concentrations, M  Based on these data, the rate equation is

If uncertainty in position and momentum are equal, then uncertainty in velocity is

The dissociation equilibrium of a gas $\mathrm{AB}_2$ can be represented as, $2 \mathrm{AB}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{AB}(\mathrm{g})+\mathrm{B}_2(\mathrm{~g})$. The degree of dissociation is ' $\mathrm{x}$ ' and is small compared to 1. The expression relating the degree of dissociation $(\mathrm{x})$ with equilibrium constant $K_P$ and total pressure $\mathrm{P}$ is