Physical Chemistry PYQ — Page 4

The relation between ${n}_{m}$ (${n}_{m}=$the number of permissible values of magnetic quantum number $(m)$) for a given value of azimuthal quantum number $(l)$, is

The density of $1 \mathrm{M}$ solution of a compound ' $X$ ' is $1.25 \mathrm{~g} \mathrm{~mL}^{-1}$. The correct option for the molality of solution is (Molar mass of compound $X=85 \mathrm{~g}$ )

Which amongst the following aqueous solutions of electrolytes will have minimum elevation in boiling point? Choose the correct option.

For a weak acid $\mathrm{HA}$, the percentage of dissociation is nearly $1 \%$ at equilibrium. If the concentration of acid is $0.1 \mathrm{~mol} \mathrm{~L}^{-1}$, then the correct option for its $\mathrm{K}_{\mathrm{a}}$ at the same temperature is

Which one of the following represents all isoelectronic species?

Incorrect set of quantum numbers from the following is

The $E^{\ominus}$ values for $\begin{aligned} & \mathrm{Al}^{+} / \mathrm{Al}=+0.55 \mathrm{~V} \text { and } \mathrm{Tl}^{+} / \mathrm{TI}=-0.34 \mathrm{~V} \\ & \mathrm{Al}^{3+} / \mathrm{Al}=-1.66 \mathrm{~V} \text { and } \mathrm{Tl}^{3+} / \mathrm{TI}=+1.26 \mathrm{~V}\end{aligned}$ Identify the incorrect statement.

Which amongst the following options is the correct relation between change in enthalpy and change in internal energy?

Consider the following reaction: $2 \mathrm{H}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{H}_2 \mathrm{O}(\mathrm{g}) \Delta_{\mathrm{r}} \mathrm{H}^{\circ}=-483.64 \mathrm{~kJ}$. What is the enthalpy change for decomposition of one mole of water? (Choose the right option).

Molar conductance of an electrolyte increases with dilution according to the equation: $\Lambda_{\mathrm{m}}=\Lambda_{\mathrm{m}}^{\circ}-\mathrm{A} \sqrt{\mathrm{c}}$ Which of the following statements are true? (A) This equation applies to both strong and weak electrolytes. (B) Value of the constant A depends upon the nature of the solvent. (C) Value of constant $\mathrm{A}$ is same for both $\mathrm{BaCl}_2$ and $\mathrm{MgSO}_4$. (D) Value of constant $A$ is same for both $\mathrm{BaCl}_2$ and $\mathrm{Mg}(\mathrm{OH})_2$. Choose the most appropriate answer from the options given below.

The correct option for a redox couple is

The element expected to form largest ion to achieve the nearest noble gas configuration is :

For a certain reaction, the rate $=k[A{]}^{2}[B]$, when the initial concentration of A is tripled keeping concentration of B constant, the initial rate would

On balancing the given redox reaction $a{\mathrm{Cr}}_{2}{O}_{7}^{2-}+{\mathrm{bSO}}_{3}^{2-}(\mathrm{aq})+{\mathrm{cH}}^{+}(\mathrm{aq})\overset{}{\rightarrow }2{\mathrm{aCr}}^{3+}(\mathrm{aq})+{\mathrm{bSO}}_{4}^{2-}(\mathrm{aq})+\frac{c}{2}{H}_{2}O(l)$ The coefficients $a,b,c$are found to be respectively

Given below are two statements : Statement I : The value of wave function, $\psi$ depends upon the coordinates of the electron in the atom. Statement II : The probability of finding an electron at a point within an atom is proportional to the orbital wave function. In the light of the above statements, choose the correct answer from the options given below.

The density of the solution is $2.15 \mathrm{~g} \mathrm{~mL}^{-1}$, then mass of $2.5 \mathrm{~mL}$ solution in correct significant figures is

Find the emf of the cell in which the following reaction takes place at $298K$ $\mathrm{Ni}(s)+2{\mathrm{Ag}}^{+}(0.001M)\rightarrow {\mathrm{Ni}}^{2+}(0.001M)+2\mathrm{Ag}(s)$ (Given that $E{^{\circ}}_{\mathrm{cell}}=1.05V,\frac{2.303\mathrm{RT}}{F}=0.059$ at $298K$)

The $\mathrm{pH}$ of the solution containing $50\mathrm{mL}$ each of $0.10M$ sodium acetate and $0.01M$ acetic acid is [Given ${\mathrm{pK}}_{a}$ of ${\mathrm{CH}}_{3}\mathrm{COOH}=4.57$]

$3{O}_{2}(g)\rightleftharpoons 2{O}_{3}(g)$ for the above reaction at $298K,{K}_{c}$ is found to be $3.0\times {10}^{-59}$. If the concentration of ${O}_{2}$ at equilibrium is $0.040M$ then concentration of ${O}_{3}$ in $M$ is

Two half cell reactions are given below : $\mathrm{CO}^{3+}+\mathrm{e}^{-} \rightarrow \mathrm{Co}^{2+}, \mathrm{E}^{\circ} \mathrm{Co}^{2+} / \mathrm{Co}^{3+}=-1.81 \mathrm{~V}$ $2 \mathrm{Al}^{3+}+6 \mathrm{e}^{-} \rightarrow 2 \mathrm{Al}(\mathrm{s}), \mathrm{E}^{\mathrm{o}} \mathrm{Al} / \mathrm{Al}^{3+}=+1.66 \mathrm{~V}$ The standard EMF of a cell with feasible redox reaction will be :

Match List-I with List-II:  Choose the correct answer from the options given below :

One mole of an ideal gas at $300 \mathrm{~K}$ is expanded isothermally from $1 \mathrm{~L}$ to $10 \mathrm{~L}$ volume. $\Delta \mathrm{U}$ for this process is (Use $\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$ )

What mass of $95%$ pure ${\mathrm{CaCO}}_{3}$ will be required to neutralise $50\mathrm{mL}$ of $0.5M\mathrm{HCl}$ solution according to the following reaction? ${\mathrm{CaCO}}_{3(s)}+2{\mathrm{HCl}}_{(\mathrm{aq})}\rightarrow {\mathrm{CaCl}}_{2(\mathrm{aq})}+{\mathrm{CO}}_{2(g)}+2{H}_{2}{O}_{(l)}$ [Calculate upto second place of decimal point]

The half life of a first order reaction is 2000 years. If the concentration after 8000 years is $0.02 \mathrm{M}$, then the initial concentration was :