Physical Chemistry PYQ — Page 24

When the hydrogen ion concentration $[{H}^{+}]$changes by a factor of $1000$ , the value of $\mathrm{pH}$ of the solution

The product, which is not obtained during the electrolysis of brine solution is

The value of $\mathrm{log}K$ for the reaction $A\rightleftharpoons B$ at $298K$ is $_______.$ (Nearest integer) Given: $\Delta H^{\circ}=-54.07\mathrm{kJ}{\mathrm{mol}}^{-1}$ $\Delta S^{\circ}=10{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}$ (Taken $2.303\times 8.314\times 298=5705$ )

The number of endothermic process/es from the following is _______. A. ${I}_{2}(g)\rightarrow 2I(g)$ B. $\mathrm{HCl}(g)\rightarrow H(g)+\mathrm{Cl}(g)$ C. ${H}_{2}O(l)\rightarrow {H}_{2}O(g)$ D. $C(s)+{O}_{2}(g)\rightarrow {\mathrm{CO}}_{2}(g)$ E. Dissolution of ammonium chloride in water

Given below are two statements: Statement-I : Methyl orange is a weak acid. Statement-II : The benzenoid form of methyl orange is more intense/deeply coloured than the quinonoid form. In the light of the above statement, choose the most appropriate answer from the options given below:

The density of a monobasic strong acid (Molar mass $24.2g\mathrm{mol})$ is $1.21\mathrm{kg}L$. The volume of its solution required for the complete neutralization of $25\mathrm{mL}$ of $0.24M\mathrm{NaOH}$ is ${10}^{-2}\mathrm{mL}$ (Nearest integer)

If the degree of dissociation of aqueous solution of weak monobasic acid is determined to be $0.3$, then the observed freezing point will be _____ $%$ higher than the expected/theoretical freezing point. (Nearest integer).

The density of $3M$ solution of $\mathrm{NaCl}$ is $1.0g{\mathrm{mL}}^{-1}$. Molality of the solution is $______\times {10}^{-2}m$ (Nearest integer). Given: Molar mass of $\mathrm{Na}$ and $\mathrm{Cl}$ is $23$ and $35.5g$ ${\mathrm{mol}}^{-1}$ respectively.

A solution is prepared by adding $2g$ of $''X''$ to $1$ mole of water. Mass percent of $''X''$in solution is

The number of units, which are used to express concentration of solutions from the following is _________. (Mass percent, Mole, Mole fraction, Molarity, ppm, Molality.)

At $25^{\circ}C$, the enthalpy of the following processes are given: ${H}_{2}(g)+{O}_{2}(g)\rightarrow 2\mathrm{OH}(g)\Delta {H}^{o}=78\mathrm{kJ}{\mathrm{mol}}^{-1}$ ${H}_{2}(g)+1/2{O}_{2}(g)\rightarrow {H}_{2}O(g)\Delta {H}^{0}=-242\mathrm{kJ}{\mathrm{mol}}^{-1}$ ${H}_{2}(g)\rightarrow 2H(g)\Delta {H}^{o}=436\mathrm{kJ}{\mathrm{mol}}^{-1}$ $1/2{O}_{2}(g)\rightarrow O(g)\Delta {H}^{0}=249\mathrm{kJ}{\mathrm{mol}}^{-1}$ What would be the value of X for the following reaction? (Nearest integer) ${H}_{2}O(g)\rightarrow H(g)+\mathrm{OH}(g)\Delta {H}^{o}=X{\mathrm{kJmol}}^{-1}$

The wavelength of an electron of kinetic energy $4.50\times {10}^{-29}J$ is $________\times 10–5m.$ (Nearest integer) Given: mass of electron is$9\times 10–31\mathrm{kg},h=6.6\times 10–34\mathrm{Js}$

The osmotic pressure of solutions of PVC in cyclohexanone at $300K$ are plotted on the graph. The molar mass of PVC is $g{\mathrm{mol}}^{-1}$ (Nearest integer)  (Given : $R=0.083L\mathrm{atm}{K}^{-1}{\mathrm{mol}}^{-1}$ )

Given (A) $2\mathrm{CO}(g)+{O}_{2}(g)\rightarrow 2{\mathrm{CO}}_{2}(g){\Delta H}_{1}^{o}=-x\mathrm{kJ}{\mathrm{mol}}^{-1}$ (B) $C(\mathrm{graphite})+{O}_{2}(g)\rightarrow {\mathrm{CO}}_{2}(g){\Delta H}_{2}^{o}=-y\mathrm{kJ}{\mathrm{mol}}^{-1}$ The $\Delta {H}^{o}$ for the reaction $C(\mathrm{graphite})+\frac{1}{2}{O}_{2}(g)\rightarrow \mathrm{CO}(g)$ is

The total number of intensive properties from the following is........... Volume, Molar heat capacity, molarity, ${E}_{\mathrm{cell}}^{o}$,Gibbs free energy change, Molar mass, Mole

Henry Moseley studied characteristic $X$-ray spectra of elements. The graph which represents his observation correctly is Given $v=$ Frequency of X-ray emitted $Z=$ Atomic number

$4.5$ moles each of hydrogen and iodine is heated in a sealed ten litre vessel.At equilibrium, $3$ moles of $\mathrm{HI}$ were found. The equilibrium constant for ${H}_{2}(g)+{I}_{2}(g)\rightleftharpoons 2{\mathrm{HI}}_{(g)}$ is ........

The wave function $(\Psi )$ of $2s$ is given by ${\Psi }_{2s}=\frac{1}{2\sqrt{2\pi }}{(\frac{1}{{a}_{0}})}^{1/2}(2-\frac{r}{{a}_{0}}){e}^{-r/2{a}_{0}}$ At $r={r}_{0}$, radial node is formed. Thus, ${r}_{0}$ in terms of ${a}_{0}$

$A(g)\rightarrow 2B(g)+C(g)$ is a first order reaction. The initial pressure of the system was found to be $800\mathrm{mm}\mathrm{Hg}$ which increased to $1600\mathrm{mm}\mathrm{Hg}$ after $10\mathrm{min}$. The total pressure of the system after $30$min will be $\mathrm{mm}\mathrm{Hg}$. (Nearest integer)

Some amount of dichloromethane $({\mathrm{CH}}_{2}{\mathrm{Cl}}_{2})$ is added to $671.141\mathrm{mL}$ of chloroform $({\mathrm{CHCl}}_{3})$ to prepare $2.6\times {10}^{-3}M$ solution of ${\mathrm{CH}}_{2}{\mathrm{Cl}}_{2}(\mathrm{DCM})$. The concentration of $\mathrm{DCM}$ is _____ ppm (by mass). Given: Atomic mass : $C=12;H:1;\mathrm{Cl}=35.5$ density of ${\mathrm{CHCl}}_{3}=1.49g{\mathrm{cm}}^{-3}$

The enthalpy change for the conversion of $\frac{1}{2}{\mathrm{Cl}}_{2}$ (g) to ${\mathrm{Cl}}^{-}(\mathrm{aq})$ is $(-)$ ${\mathrm{kJmol}}^{-1}$ (Nearest integer) Given : ${\Delta }_{\text{dis }}{H}_{{\mathrm{Cl}}_{2(g)}}^{0}=240{\mathrm{kJmol}}^{-1}$. ${\Delta }_{\mathrm{eg}}{H}_{\mathrm{Cl}(g)}^{o}=-350{\mathrm{kJmol}}^{-1}$, ${\Delta }_{\mathrm{hyd}}{H}_{{\mathrm{Cl}}_{(g)}^{-}}^{o}=-380{\mathrm{kJmol}}^{-1}$

What weight of glucose must be dissolved in $100g$ of water to lower the vapour pressure by $0.20\mathrm{mm}\mathrm{Hg}$? (Assume dilute solution is being formed) Given: Vapour pressure of pure water is $54.2\mathrm{mm}\mathrm{Hg}$ at room temperature.Molar mass of glucose is $180g{\mathrm{mol}}^{-1}$

If wavelength of the first line of the Paschen series of hydrogen atom is $720\mathrm{nm}$, then the wavelength of the second line of this series is _______ $\mathrm{nm}$. (Nearest integer)

The energy of one mole of photons of radiation of frequency $2\times {10}^{12}\mathrm{Hz}$ in ${\mathrm{Jmol}}^{-1}$ is _____ . (Nearest integer) (Given: $h=6.626\times {10}^{-34}\mathrm{Js}$ ${N}_{A}=6.022\times {10}^{23}{\mathrm{mol}}^{-1}$)