Physical Chemistry PYQ — Page 35

Among the following the number of state variable is Internal energy $(U)$ Volume $(V)$ Heat $(q)$ Enthalpy $(H)$

$2g$ of a non-volatile non-electrolyte solute is disolved in $200g$ of two different solvents $A$ and $B$ whose ebullioscopic constants are in the ratio of $1:8$. The elevation in boiling points of $A$ and $B$ are in the ratio $\frac{x}{y}(x:y)$. The value of $y$ is____(Nearest Integer)

$\mathrm{CNG}$ is an important transportation fuel. When $100\mathrm{gCNG}$ is mixed with $208g$ oxygen in vehicles, it leads to the formation of ${\mathrm{CO}}_{2}$ and ${H}_{2}O$ and produces large quantity of heat during this combustion, then the amount of carbon dioxide, produced in grams is [nearest integer] [Assume CNG to be methane]

$1.2\mathrm{mL}$ of acetic acid is dissolved in water to make $2.0L$ of solution. The depression in freezing point observed for this strength of acid is $0.0198^{\circ}C$. The percentage of dissociation of the acid is (Nearest integer) [Given : Density of acetic acid is $1.02g{\mathrm{mL}}^{-1}$ Molar mass of acetic acid is $60g{\mathrm{mol}}^{-1}$ ${K}_{f}({H}_{2}O)=1.85K\mathrm{kg}{\mathrm{mol}}^{-1}$]

Solute A associates in water. When $0.7g$ of solute $A$ is dissolved in $42.0g$ of water, it depresses the freezing point by $0.2^{\circ}C$. The percentage association of solute $A$ in water, is [Given: Molar mass of $A=93g{\mathrm{mol}}^{-1}$. Molal depression constant of water is $1.86K\mathrm{kg}{\mathrm{mol}}^{-1}$]

The osmotic pressure exerted by a solution prepared by dissolving $2.0g$ of protein of molar mass $60\mathrm{kg}{\mathrm{mol}}^{-1}$ in $200\mathrm{mL}$ of water at $27^{\circ}C$ is____$\mathrm{Pa}$. [integer value] (use $R=0.083L$ bar ${\mathrm{mol}}^{-1}{K}^{-1}$)

$116g$ of a substance upon dissociation reaction, yields $7.5g$ of hydrogen, $60g$ of oxygen and $48.5g$ of carbon. Given that the atomic masses of $H,O$ and $C$ are $1,16$ and $12$, respectively. The data agrees with how many formulae of the following? A. ${\mathrm{CH}}_{3}\mathrm{COOH}$ B. $\mathrm{HCHO}$ C. ${\mathrm{CH}}_{3}{\mathrm{OOCH}}_{3}$ D. ${\mathrm{CH}}_{3}\mathrm{CHO}$

The vapour pressures of two volatile liquids $A$ and $B$ at $25^{\circ}C$ are $50$ Torr and $100$ Torr, respectively. If the liquid mixture contains $0.3$ mole fraction of $A$, then the mole fraction of liquid $B$ in the vapour phase is $\frac{x}{17}$. The value of $x$ is

When $600\mathrm{mL}$ of $0.2M{\mathrm{HNO}}_{3}$ is mixed with $400\mathrm{mL}$ of $0.1M\mathrm{NaOH}$ solution in a flask, the rise in temperature of the flask is_____$\times {10}^{-2}^{\circ}C$ (Enthalpy of neutralisation $=57\mathrm{kJ}{\mathrm{mol}}^{-1}$ and Specific heat of water $=4.2{\mathrm{JK}}^{-1}{g}^{-1}$) (Neglect heat capacity of flask)

The number of radial and angular nodes in $4d$ orbital are, respectively

For a reaction at equilibrium $A(g)\rightleftharpoons B(g)+\frac{1}{2}C(g)$ the relation between dissociation constant $(K)$, degree of dissociation $(\alpha )$ and equilibrium pressure $(p)$ is given by :

Chlorophyll extracted from the crushed green leaves was dissolved in water to make $2L$ solution of $\mathrm{Mg}$ of concentration $48 \mathrm{ppm}$. The number of atoms of $\mathrm{Mg}$ in this solution is $x\times {10}^{20}$ atoms. The value of $x$ is (Nearest Integer) (Given : Atomic mass of $\mathrm{Mg}$ is $24g{\mathrm{mol}}^{-1}$, ${N}_{A}=6.02\times {10}^{23}{\mathrm{mol}}^{-1}$)

Two solutions $A$ and $B$ are prepared by dissolving $1g$ of non-volatile solutes $X$ and $Y$. respectively in $1\mathrm{kg}$ of water. The ratio of depression in freezing points for $A$ and $B$ is found to be $1:4$. The ratio of molar masses of $X$ and $Y$ is

The molar heat capacity for an ideal gas at constant pressure is $20.785J{K}^{-1}{\mathrm{mol}}^{-1}$. The change in internal energy is $5000J$ upon heating it from $300K$ to $500K$. The number of moles of the gas at constant volume is____ (Given: $R=8.314J{K}^{-1}{\mathrm{mol}}^{-1}$)

$17.0g$ of ${\mathrm{NH}}_{3}$ completely vapourises at $-33.42^{\circ}C$ and $1$ bar pressure and the enthalpy change in the process is $23.4\mathrm{kJ}{\mathrm{mol}}^{-1}$. The enthalpy change for the vapourisation of $85g$ of ${\mathrm{NH}}_{3}$ under the same conditions is $\mathrm{kJ}$.

$2.4g$ coal is burnt in a bomb calorimeter in excess of oxygen at $298K$ and $1\mathrm{atm}$ pressure. The temperature of the calorimeter rises from $298K$ to $300K$. The enthalpy change during the combustion of coal is $-x\mathrm{kJ}{\mathrm{mol}}^{-1}$. The value of $x$ is_____(Given : Heat capacity of bomb calorimeter $20.0{\mathrm{kJK}}^{-1}$. Assume coal to be pure carbon)

When $5$ moles of $\mathrm{He}$ gas expand isothermally and reversibly at $300K$ from $10$ litre to $20$ litre, the magnitude of the maximum work obtained is $J$. [nearest integer ] (Given : $R=8.3J{K}^{-1}{\mathrm{mol}}^{-1}$ and $\mathrm{log}2=0.3010$)

For combustion of one mole of magnesium in an open container at $300K$ and $1$ bar pressure, ${\Delta }_{C}{H}^{\ominus }=-601.70\mathrm{kJ}{\mathrm{mol}}^{-1}$, the magnitude of change in internal energy for the reaction is $\mathrm{kJ}$. (Nearest integer) (Given : $R=8.3J{K}^{-1}{\mathrm{mol}}^{-1}$)

For complete combustion of methanol ${\mathrm{CH}}_{3}\mathrm{OH}(l)+\frac{3}{2}{O}_{2}(g)\rightarrow {\mathrm{CO}}_{2}(g)+2{H}_{2}O(l)$ the amount of heat produced as measured by bomb calorimeter is $726\mathrm{kJ}{\mathrm{mol}}^{-1}$ at $27^{\circ}C$. The enthalpy of combustion for the reaction is $-x\mathrm{kJ}{\mathrm{mol}}^{-1}$, where $x$ is integer) (Given : $R=8.3{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}$)

At $298K$, the equilibrium constant is $2\times {10}^{15}$ for the reaction: $\mathrm{Cu}(s)+2{\mathrm{Ag}}^{+}(\mathrm{aq})\rightleftharpoons {\mathrm{Cu}}^{2+}(\mathrm{aq})+2\mathrm{Ag}(s)$ The equilibrium constant for the reaction $\frac{1}{2}{\mathrm{Cu}}^{2+}(\mathrm{aq})+\mathrm{Ag}(s)\rightleftharpoons \frac{1}{2}\mathrm{Cu}(s)+{\mathrm{Ag}}^{+}(\mathrm{aq})$ is $x\times {10}^{-8}$. The value of $x$ is ______. (Round off the answer to the nearest integer)

$2\mathrm{NOCl}(g)\rightleftharpoons 2\mathrm{NO}(g)+{\mathrm{Cl}}_{2}(g)$ In an experiment, $2.0$ moles of $\mathrm{NOCl}$ was placed in a one-litre flask and the concentration of $\mathrm{NO}$ after equilibrium established, was found to be $0.4\mathrm{mol}/L$. The equilibrium constant at $30^{\circ}C$ is_____$\times {10}^{-4}$.

If the solubility product of $\mathrm{PbS}$ is $8\times {10}^{-28}$, then the solubility of $\mathrm{PbS}$ in pure water at $298K$ is $x\times {10}^{-16}\mathrm{mol}{L}^{-1}$. The value of $x$ is____ (Nearest integer) [Given $\sqrt{2}=1.41$]

For the reaction given below: ${\mathrm{CoCl}}_{3}.{\mathrm{xNH}}_{3}+{\mathrm{AgNO}}_{3}(\mathrm{aq})\rightarrow$ If two equivalents of $\mathrm{AgCl}$ precipitate out, then the value of $x$ will be _______

$200\mathrm{mL}$ of $0.01\mathrm{MHCl}$ is mixed with $400\mathrm{mL}$ of $0.01{\mathrm{MH}}_{2}{\mathrm{SO}}_{4}$. The $\mathrm{pH}$ of the mixture is