Physical Chemistry PYQ — Page 53

At $35{}^{o}C,$ the vapour pressure of $C{S}_{2},$ is $512mm$ Hg and that of acetone is $144mmHg.$ A solution of $C{S}_{2}$ in acetone has a total vapour pressure of $600 mmHg$ . The false statement amongst the following is:

For one mole of an ideal gas, which of these statements must be true? (a) Internal energy $(U)$ and enthalpy $(H)$ each depends on temperature. (b) Compressibility factor $Z$ is not equal to 1 (c) ${C}_{P,m}–{C}_{V,m}=R$ (d) $\mathrm{dU}={C}_{v}\mathrm{dT}$ for any process

The difference between $\Delta H$ and $\Delta U$ is $(\Delta H-\Delta U)$, when the combustion of one mole of heptane $(l)$ is carried out at a temperature $T$ , is equal to:

The de Broglie wavelength $(\lambda)$ associated with a photoelectron varies with the frequency $(v)$ of the incident radiation as,$\left[v_{0}\right.$ is threshold frequency]:

A process will be spontaneous at all temperatures if:

The molar solubility of $Cd{(OH)}_{2}$ is $1.84\times {10}^{-5}M$ in water. The expectes solunility of $Cd{(OH)}_{2}$ in a buffer solution of $pH=12$ is:

For the reaction, $2A+B\rightarrow$ products, when the concentration of $A$ and $B$ both were doubled, the rate of the reaction increased from $0.3 mol {L}^{-1}{s}^{-1}$ to $2.4 mol {L}^{-1}{s}^{-1}.$ When the concentration of $A$ alone is doubled, the rate increased from $0.3 mol {L}^{-1}{s}^{-1}$ to $0.6 mol {L}^{-1}{s}^{-1}.$ Which one of the following statements is correct?

For the equilibrium $2 \mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{OH}^{-} ;$ the value of $\Delta \mathrm{G}^{\circ}$ at $298 \mathrm{~K}$ is approximately:

Given: $C{o}^{3+}+{e}^{-}\rightarrow C{o}^{2+};E^{\circ}=+1.81V$ ${Pb}^{3+}+{2e}^{-}\rightarrow {Pb}^{2+};E^{\circ}=+1.67V$ $C{e}^{4+}+{e}^{-}\rightarrow C{e}^{3+};E^{\circ}=+1.61V$ ${Bi}^{3+}+{3e}^{-}\rightarrow Bi;E^{\circ}=+0.20V$ Oxidizing power of the species will increase in the order:

Enthalpy of sublimation of iodine is $24 cal {g}^{-1}$ at $200^{\circ}C$ . If specific heat of ${I}_{2}$ (s) and ${I}_{2}$ (vap) are $0.055$ and $0.031 cal {g}^{-1}{K}^{-1}$ respectively, then enthalpy of sublimation of iodine at $250^{\circ}C$ in $cal {g}^{-1}$ is:

If $p$ is the momentum of the fastest electron ejected from a metal surface after the irradiation of light having wavelength $\lambda ,$ then for $1.5 p$ momentum of the photoelectron, the wavelength of the light should be: (Assume kinetic energy of ejected photoelectron to be very high in comparison to work function)

Which one of the following about an electron occupying the 1s orbital in a hydrogen atom is incorrect? (The Bohr radius is represented by ${a}_{0}$ ).

The $pH$ of a $0.02 M$ $N{H}_{4}Cl$ solution will be [Given: ${K}_{b}(N{H}_{4}OH)={10}^{-5}$ and $\mathrm{log}⁡2=0.301$]

For emission line of atomic hydrogen from ${n}_{i}=8$ to ${n}_{f}=n,$ the plot of wave number $(\overset{-}{v})$ against $(\frac{1}{{n}^{2}})$ will be: (The Rydberg constant, ${R}_{H}$ is in wave number unit)

The standard reaction Gibbs energy for a chemical reaction at an absolute temperature $\mathrm{T}$ is given by $\Delta \mathrm{G}^{\circ}=\mathrm{A}-\mathrm{BT}$ where A and $B$ are non-zero constants. Which of the following is true about this reaction?

$\mathrm{K}_{2} \mathrm{HgI}_{4}$ is $40 \%$ ionised in aqueous solution. The value of its van't Hoff factor (i) is:

In order to oxidize a mixture of one mole of each of $Fe{C}_{2}{O}_{4},F{e}_{2}{({C}_{2}{O}_{4})}_{3},FeS{O}_{4}$ and $F{e}_{2}{(S{O}_{4})}_{3}$ in acidic medium, the number of moles of $KMn{O}_{4}$ is:

The mole fraction of a solvent in aqueous solution of a solute is $0.8.$ The molality (in mol ${kg}^{-1}$ ) of the aqueous solution is:

$25 g$ of an unknown hydrocarbon upon burnig produces $88 g$ of $C{O}_{2}$ and $9g$ of ${H}_{2}O.$ This unknown hydrocarbon contains:

Among the following, the energy of $2s$ orbital is lowest in:

For silver, ${C}_{p}(J{K}^{-1}mo{l}^{-1})=23+0.01T.$ If the temperature $(T)$ of $3$ moles of silver is raised from $300 K to 1000 K at 1 atm$ pressure, the value of $\Delta H$ will be close to:

Which one of the following graphs between molar conductivity $({\Lambda }_{m})$ versus $\sqrt{C}$ is correct?

$50 \mathrm{mL}$ of $0.5 M$ oxalic acid is needed to neutralize $25 \mathrm{mL}$ of sodium hydroxide solution. What is the amount of $\mathrm{NaOH}$ in $50 \mathrm{mL}$ of the given sodium hydroxide solution?

A solution of $Ni{(N{O}_{3})}_{2}$ is electrolyzed between platinum electrode $0.1$ Faraday electricity. How many mole of $Ni$ will be deposited at the cathode?