Physical Chemistry PYQ — Page 51

For a dimerization reaction, $2A(g)\rightarrow {A}_{2}(g)$ at $298K,\Delta {U}^{-}=-20{\mathrm{kJmol}}^{-1},\Delta {S}^{-}=-30{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}$,then the $\Delta {G}^{-}$ will be …..J.

The solubility product of $Cr{(OH)}_{3}$ at $298K$ is $6.0\times {10}^{-31}.$ The concentration of hydroxide ions in a saturated solution of $Cr{(OH)}_{3}$ will be

For the equilibrium $A\rightleftharpoons B$, the variation of the rate of the forward (a) and reverse (b) reaction with time is given by:

For a reaction $4M(s)+{\mathrm{nO}}_{2}(g)\rightarrow 2{M}_{2}{O}_{n}(s)$ The free energy change is plotted as a function of temperature. The temperature below which the oxide is stable could be inferred from the plot as the point at which :

A soft drink was bottled with a partial pressure of ${\mathrm{CO}}_{2}$ of 3 bar over the liquid at room temperature. The partial pressure of ${\mathrm{CO}}_{2}$ over the solution approaches a value of 30 bar when $44g$ of ${\mathrm{CO}}_{2}$ is dissolved in $1\mathrm{kg}$ of water at room temperature. The approximate $\mathrm{pH}$ of the soft drink is ___________$\times {10}^{-1}$. (First dissociation constant of ${H}_{2}{\mathrm{CO}}_{3}=4.0\times {10}^{-7};\mathrm{log}2=0.3;$ density of the soft drink $=1g{\mathrm{mL}}^{-1}$)

Let ${C}_{\mathrm{NaCl}}$ and ${{C}_{\mathrm{BaSO}}}_{4}$, be the conductances (in S) measured for saturated aqueous solutions of $\mathrm{NaCl}$ and $BaS{O}_{4}$ respectively, at a temperature T. Which of the following is false?

$100\mathrm{mL}$ of $0.1M\mathrm{HCl}$ is taken in a beaker and to it $100\mathrm{mL}$ $0.1M\mathrm{NaOH}$ of is added in steps of $2\mathrm{mL}$ and the $\mathrm{pH}$ is continuously measured. Which of the following graphs correctly depicts the change in $\mathrm{pH}$ ?

$250\mathrm{mL}$ of a waste solution obtained from the workshop of a goldsmith contains $0.1M{\mathrm{AgNO}}_{3}$ and $0.1M\mathrm{AuCl}$. The solution was electrolyzed at $2V$ by passing a current of $1A$ for $15$ minutes. The metal/metals electrodeposited will be : $({\text{E}}_{{\text{Ag}}^{+}/\text{Ag}}^{0}=0.80\text{V},{\text{E}}_{{\text{Au}}^{+}/\text{Au}}^{0}=1.69\text{V})$

The molarity of ${HNO}_{3}$ in a sample which has density $1.4g/mL$ and mass percentage of $63%$ is ________ (Molecular Weight of ${HNO}_{3}=63$ )

Preparation of Bakelite proceeds via reactions:

The average molar mass of chlorine is $35.5g{\mathrm{mol}}^{-1}$. The ratio of $\mathrm{Cl}35$ to $\mathrm{Cl}37$ in naturally occurring chlorine is close to :

An open beaker of water in equilibrium with water vapour is in a sealed container. When a few grams of glucose are added to the beaker of water, the rate at which water molecules :

The mass of ammonia in grams produced when $2.8\mathrm{kg}$ of dinitrogen quantitatively reacts with $1\mathrm{kg}$ of dihydrogen is _____

The stoichiometry and solubility product of a salt with the solubility curve given below is, respectively: 

At constant volume, $4mol$ of an ideal gas when heated from $300K$ to $500K$ changes its internal energy by $5000J.$ The molar heat capacity at constant volume is ________

A cylinder containing an ideal gas ( $0.1mol$ of $1.0d{m}^{3}$ ) is in thermal equilibrium with a large volume of $0.5$ molal aqueous solution of ethylene glycol at its freezing point. If the stoppers ${S}_{1}$ and ${S}_{2}$ (as shown in the figure) are suddenly withdrawn, the volume of the gas in litres after equilibrium is achieved will be _____________. (Given, ${K}_{f}(water)=2.0Kkgmo{l}^{-1},R=0.08d{m}^{3}atm{K}^{-1}mo{l}^{-1})$ 

The elevation of boiling point of $0.10m$ aqueous ${\mathrm{CrCl}}_{3}.{\mathrm{xNH}}_{3}$ solution is two times that of $0.05m$ aqueous ${\mathrm{CaCl}}_{2}$ solution. The value of $x$ is $\ldots \ldots \ldots \ldots ..$ [Assume $100%$ ionisation of the complex and ${\mathrm{CaCl}}_{2},$ coordination number of $\mathrm{Cr}$ as $6,$ and that all ${\mathrm{NH}}_{3}$ molecules are present inside the coordination sphere]

For the reaction; $A(l)\rightarrow 2B(g)$ $\Delta U=2.1kcal,\Delta S=20cal{K}^{-1}$ at $300K.$ Hence $\Delta G$ in $kcal$ is _____________.

The internal energy change (in $J$) when $90g$ of water undergoes complete evaporation at $100^{\circ}C$ is .............. (Given : ${\Delta H}_{\mathrm{vap}}$ for water at $373K=41\mathrm{kJ}/\mathrm{mol}$, $R=8.314{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1}$)

If $75%$ of a first order reaction was completed in $90$ minutes, $60%$ of the same reaction would be completed in approximately (in minutes) _____ (Take: $\mathrm{log}2=0.30;\mathrm{log}2.5=0.40$)

What would be the electrode potential for the given half-cell reaction at $pH=5?_________.$ $2{H}_{2}O\rightarrow {O}_{2}+4\overset{\oplus }{\text{H}}+4{e}^{-};{E}_{red}^{0}=1.23V$ $(R=8.314J{mol}^{-1}{K}^{-1};Temp=298K;oxygen under s\mathrm{tan}dard .atm.pressureof1bar)$

Given that the standard potentials $({E}^{o})$ of ${\mathrm{Cu}}^{2+}/\mathrm{Cu}$ and ${\mathrm{Cu}}^{+}/\mathrm{Cu}$ are $0.34V$ and $0.522V$ respectively, the ${E}^{o}$ of ${\mathrm{Cu}}^{2+}/{\mathrm{Cu}}^{+}$ is:

While titration dilute $\mathrm{HCI}$ solution with aqueous $\mathrm{NaOH}$, which of the following will not be required ?

For a reaction $X+Y=2Z,1.0\mathrm{mol}$ of $X,1.5\mathrm{mol}$ of $Y$ and $0.5\mathrm{mol}$ of $Z$ were taken in a $1L$ vessel and allowed to react. At equilibrium, the concentration of $Z$ was $1.0{\mathrm{molL}}^{-1}$. the equilibrium constant of the reaction is $\ldots \ldots \ldots \ldots \frac{x}{15}.$ The value of x is $\ldots \ldots .$