Physical Chemistry PYQ — Page 13

A reaction is $50 \%$ complete in 2 hours and $75 \%$ complete in 4 hours. The order of reaction is:

Which is the strongest acid in the following?

The value of Planck's constant is $6.63 \times 10^{-34} \mathrm{Js}$. The speed of light is $3 \times 10^{17} \mathrm{nms}^{-1}$. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of $6 \times 10^{15} \mathrm{~s}^{-1} ?$

A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of $\mathrm{pH}=10$ and by passing hydrogen gas around the platinum wire at $1 \mathrm{~atm}$ pressure. The oxidation potential of electrode would be

A button cell used in watches functions as following $\mathrm{Zn}(s)+\mathrm{Ag}_2 \mathrm{O}(s) & +\mathrm{H}_2 \mathrm{O}(l) \rightleftharpoons 2 \mathrm{Ag}(s) + \mathrm{Zn}^{2+}(\alpha q)+2 \mathrm{OH}^{-}(\alpha q)$ If half cell potentials are $\begin{aligned} \mathrm{Zn}^{2+}(a q)+2 e^{-} & \rightarrow \mathrm{Zn}(s) ; E^{\circ}=-0.76 \mathrm{~V} \\ \mathrm{Ag}_2 \mathrm{O}(s)+\mathrm{H}_2 \mathrm{O}(l) & +2 e^{-} \\ & \rightarrow 2 \mathrm{Ag}(s)+2 \mathrm{OH}^{-}(a q), \\ & E^{\circ}=0.34 \mathrm{~V} \end{aligned}$ The cell potential will be

Which of these is least likely to act as a Lewis base?

At $25^{\circ} \mathrm{C}$ molar conductance of 0.1 molar aqueous solution of ammonium hydroxide is $9.54 \mathrm{ohm}^{-1} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$ and at infinite dilution its molar conductance is $238 \mathrm{ohm}^{-1} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$. The degree of ionisation of ammonium hydroxide at the same concentration and temperature is

In an experiment it is shown that $10 \mathrm{ml}$ of $0.05 \mathrm{M}$ solution of chloride required 10 $\mathrm{ml}$ of $0.1 \mathrm{M}$ solution of $\mathrm{AgNO}_3$, which of the following will be the formula of the chloride ( $\mathrm{X}$ stands for the symbol of the element other than chlorine)

The value of $\mathrm{K}_{s p}$ of $\mathrm{CaCO}_3$ and $\mathrm{CaC}_2 \mathrm{O}_4$ are $4.7 \times 10^{-9}$ and $1.3 \times 10^{-9}$ respectively at $25^{\circ} \mathrm{C}$. If the mixture of these two is washed with water, what is the concentration of $\mathrm{Ca}^{2+}$ ions in water?

Which condition is not satisfied by an ideal solution?

How many gram of cobalt metal will be deposited when a solution of cobalt (II) chloride is electrolyzed with a current of 10 amperes for 109 minutes (1 Faraday = $96,500 \mathrm{C}$; Atomic mass of $\mathrm{Co}=59 u$ )

The dissociation constant of a weak acid is $1 \times 10^{-4}$. In order to prepare a buffer solution with a pH $=5$, the [Salt]/ [Acid] ratio should be:

Limiting molar conductivity of $\mathrm{NH}_4 \mathrm{OH~} \left( \text{i.e., } \stackrel{\circ}{\Lambda}_{m\left(\mathrm{NH}_4 \mathrm{OH}\right)}\right)$ is equal to

Given the reaction between two gases represented by $A_2$ and $B_2$ to give the compound $A B(g)$. $$ A_2(g)+B_2(g) \rightleftharpoons 2 A B(g) $$ At equilibrium, the concentration of $A_2=3.0 \times 10^{-3} \mathrm{M}$ of $B_2=4.2 \times 10^{-3} \mathrm{M}$ of $A B=2.8 \times 10^{-3} \mathrm{M}$ If the reaction takes place in a sealed vessel at $527^{\circ} \mathrm{C}$, then the value of $K_c$ will be

Standard reduction potentials of the half reactions are given below $$ \begin{array}{ll} \mathrm{F}_2(g)+2 e^{-} \longrightarrow 2 \mathrm{~F}^{-}(a q) ; & E^{\circ}=+2.85 \mathrm{~V} \\ \mathrm{Cl}_2(g)+2 e^{-} \longrightarrow 2 \mathrm{Cl}^{-}(a q) ; & E^{\circ}=+1.36 \mathrm{~V} \\ \mathrm{Br}_2(l)+2 e^{-} \longrightarrow 2 \mathrm{Br}^{-}(a q) ; & E^{\circ}=+1.06 \mathrm{~V} \\ \mathrm{I}_2(s)+2 e^{-} \longrightarrow 2 \mathrm{I}^{-}(a q) ; & E^{\circ}=+0.53 \mathrm{~V} \end{array} $$ The strongest oxidising and reducing agents respectively are

Four successive members of the first series of the transition metals are listed below. For which one of them the standard potential $\left(E_{M^{2+} / M}^{\circ}\right)$ value has a positive sign?

Molar conductivities $\left(\Lambda_m^{\circ}\right)$ at infinite dilution of $\mathrm{NaCl}, \mathrm{HCl}$ and $\mathrm{CH}_3 \mathrm{COONa}$ are 126.4, 425.9 and $91.0 \mathrm{~S} \mathrm{~cm} \mathrm{cmol}^{-1}$ respectively. $\Lambda^{\circ}{ }_m$ for $\mathrm{CH}_3 \mathrm{COOH}$ will be

A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the reaction which element undergoes maximum change in the oxidation number?

$p_A$ and $p_B$ are the vapour pressure of pure liquid components, $A$ and $B$, respectively of an ideal binary solution. If $x_A$ represents the mole fraction of component $A$, the total pressure of the solution will be

In a zero order reaction for every $10^{\circ}$ rise of temperature, the rate is doubled. If the temperature is increased from $10^{\circ} \mathrm{C}$ to $100^{\circ} \mathrm{C}$, the rate of the reaction will become

In which of the following compounds, nitrogen exhibits highest oxidation state?

In a reaction, $A+B \rightarrow$ Product, rate is doubled when the concentration of $B$ is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants $(A$ and $B$ ) are doubled. Rate law for the reaction can be written as

Standard enthalpy of vaporisation $\Delta_{\mathrm{vap}} H^{\mathrm{s}}$ for water at $100^{\circ} \mathrm{C}$ is $40.66 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The internal energy of vaporisation of water at $100^{\circ} \mathrm{C}$ (in $\left.\mathrm{kJ} \mathrm{mol}^{-1}\right)$ is (Assume water vapour to behave like an ideal gas).

In which of the following reactions, standard reaction entropy changes $\left(\Delta S^{\circ}\right)$ is positive and standard Gibb's energy change $\left(\Delta G^{\circ}\right)$ decreases sharply with increasing temperature?