Physical Chemistry PYQ — Page 72

Rate of a reaction can be expressed by Arrhenius equation as: $$ \mathrm{k}=\mathrm{Ae}^{-\mathrm{E} / \mathrm{RT}} $$ In this equation, E represents

Which of the following statements is true?

The "spin-only" magnetic moment [in units of Bohr magneton, $\left.\left(\mu_{\mathrm{B}}\right)\right]$ of $\mathrm{Ni}^{2+}$ in aqueous solution would be (Atomic number of $\mathrm{Ni}=28$ )

The standard enthalpy of formation $\left(\Delta_{\mathrm{f}} \mathrm{H}^{\circ}\right)$ at $298 \mathrm{~K}$ for methane, $\mathrm{CH}_4(\mathrm{~g})$, is $-74.8 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The additional information required to determine the average energy for $\mathrm{C}-\mathrm{H}$ bond formation would be

Uncertainty in the position of an electron (mass $=9.1 \times 10^{-31} \mathrm{~kg}$ ) moving with a velocity $300 \mathrm{~ms}^{-1}$, accurate upto $0.001 \%$, will be

An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If $T_i$ is the initial temperature and $T_f$ is the final temperature, which of the following statements is correct?

The following mechanism has been proposed for the reaction of $\mathrm{NO}$ with $\mathrm{Br}_2$ to form $\mathrm{NOBr}$ : $\mathrm{NO}(\mathrm{g})+\mathrm{Br}_2(\mathrm{~g}) \rightleftharpoons \mathrm{NOBr}_2(\mathrm{~g})$ $$ \mathrm{NOBr}_2(\mathrm{~g})+\mathrm{NO}(\mathrm{g}) \longrightarrow 2 \mathrm{NOBr}(\mathrm{g}) $$ If the second step is the rate determining step, the order of the reaction with respect to $N O(g)$ is

Resistance of a conductivity cell filled with a solution of an electrolyte of concentration $0.1 \mathrm{M}$ is $100 \Omega$. The conductivity of this solution is $1.29 \mathrm{~S} \mathrm{~m}^{-1}$. Resistance of the same cell when filled with $0.2 \mathrm{M}$ of the same solution is $520 \Omega$. The molar conductivity of $0.02 \mathrm{M}$ solution of the electrolyte will be

Density of a $2.05 \mathrm{M}$ solution of acetic acid in water is $1.02 \mathrm{~g} / \mathrm{mL}$. The molality of the solution is

Which one of the following sets of ions represents a collection of isoelectronic species?

Given the data at $25^{\circ} \mathrm{C}$, $$ \begin{aligned} & \mathrm{Ag}+\mathrm{I}^{-} \longrightarrow \mathrm{AgI}+\mathrm{e}^{-} ; \mathrm{E}^{\circ}=0.152 \mathrm{~V} \\ & \mathrm{Ag} \longrightarrow \mathrm{Ag}^{+}+\mathrm{e}^{-} ; \quad \mathrm{E}^{\circ}=-0.800 \mathrm{~V} \end{aligned} $$ What is the value of $\log \mathrm{K}_{\mathrm{sp}}$ for $\mathrm{AgI}$ ? $$ \left(2.303 \frac{R T}{F}=0.059 \mathrm{~V}\right) $$

A schematic plot of ln $\mathrm{K}_{\text {eq }}$ versus inverse of temperature for a reaction is shown below  The reaction must be

 Calculate $\wedge_{H O A c}^{\infty}$ Using appropriate molar conductances of the electrolytes listed above at infinite dilution in $\mathrm{H}_2 \mathrm{O}$ at $25^{\circ} \mathrm{C}$

Of the following sets which one does NOT contain isoelectronic species?

In a multi – electron atom, which of the following orbitals described by the three quantum numbers will have the same energy in the absence of magnetic acid and electric fields? (a) $n=1, l=0, m=0$ (b) $n=2, l=0, m=0$ (c) $n=2, l=1, m=1$ (d) $n=3, l=2, m=1$ (e) $n=3, l=2, m=0$

If we consider that $\frac{1}{6}$, in place of $\frac{1}{12}$; mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Consider the reaction: $\mathrm{N}_2+3 \mathrm{H}_2 \longrightarrow 2 \mathrm{NH}_3$ carried out at constant temperature and pressure. If $\Delta \mathrm{H}$ and $\Delta \mathrm{U}$ are the enthalpy and internal energy changes for the reaction, which of the following expressions is true?

The exothermic formation of $\mathrm{ClF}_3$ is represented by the equation: $$ \mathrm{Cl}_{2(g)}+3 \mathrm{~F}_{2(g)} \rightleftharpoons 2 \mathrm{ClF}_{3(g)} ; \Delta \mathrm{r} \mathrm{H}=-329 \mathrm{~kJ} $$ Which of the following will increase the quantity of $\mathrm{ClF}_3$ in an equilibrium mixture of $\mathrm{Cl}_2, \mathrm{~F}_2$ and $\mathrm{ClF}_3$ ?

A reaction involving two different reactants can never be

The solubility product of a salt having general formula $M X_2$, in water is: $4 \times 10^{-12}$. The concentration of $\mathrm{M}^{2+}$ ions in the aqueous solution of the salt is

Two solutions of a substance (non electrolyte) are mixed in the following manner. 480 ml of 1.5 M first solution + 520 mL of 1.2 M second solution. What is the molarity of the final mixture?

Which of the following statements in relation to the hydrogen atom is correct?

What is the conjugate base of $\mathrm{OH}^{-} ?$

Equimolar solutions in the same solvent have