NEET UG 2021 — Physical Chemistry

An organic compound contains $80%$ (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of $C$ is $12$ and of $H$ is $1$]

Which of the following reactions is the metal displacement reaction? Choose the right option.

Which one among the following is the correct option for right relationship between ${C}_{p}$ and ${C}_{v}$ for one mole of ideal gas?

The correct option for the value of vapour pressure of a solution at $45ºC$ with benzene to octane in molar ratio $3:2$ is: [At $45^{\circ}C$ vapour pressure of benzene is $280\mathrm{mm}\mathrm{Hg}$ and that of octane is $420\mathrm{mm}\mathrm{Hg}.$ Assume Ideal gas]

For a reaction $A\rightarrow B,$ enthalpy of reaction is $-4.2\mathrm{kJ}{\mathrm{mol}}^{-1}$ and enthalpy of activation is $9.6\mathrm{kJ}{\mathrm{mol}}^{-1}.$ The correct potential energy profile for the reaction is shown in the option.

From the following pairs of ions which one is not an iso-electronic pair?

For irreversible expansion of an ideal gas under isothermal condition, the correct option is:

The following solutions were prepared by dissolving $10g$ of glucose $({C}_{6}{H}_{12}{O}_{6})$ in $250\mathrm{mL}$ of water $({P}_{1}),10g$ of urea $({\mathrm{CH}}_{4}{N}_{2}O)$ in $250\mathrm{mL}$ of water $({P}_{2})$ and $10g$ of sucrose $({C}_{12}{H}_{22}{O}_{11})$ in $250\mathrm{mL}$ of water $({P}_{3}).$ The right option for the decreasing order of osmotic pressure of these solutions is:

The ${\mathrm{pK}}_{b}$ of dimethylamine and ${\mathrm{pK}}_{a}$ of acetic acid are $3.27$and $4.77$ respectively at $T(K).$ The correct option for the $\mathrm{pH}$ of dimethylammonium acetate solution is:

The molar conductivity of $0.007M$ acetic acid is $20S{\mathrm{cm}}^{2}{\mathrm{mol}}^{-1}.$ What is the dissociation constant of acetic acid? Choose the correct option. ${\lambda }_{{H}^{+}}^{\circ }=350S{\mathrm{cm}}^{2}{\mathrm{mol}}^{-1} {\lambda }_{{\mathrm{CH}}_{3}{\mathrm{COO}}^{-}}^{\circ }=50S{\mathrm{cm}}^{2}{\mathrm{mol}}^{-1}$

The unit of rate constant for zero order reaction is

The molar conductance of $\mathrm{NaCl},\mathrm{HCl}$ and ${\mathrm{CH}}_{3}\mathrm{COONa}$ at infinite dilution are $126.45,426.16$ and $91.0{\mathrm{Scm}}^{2}{\mathrm{mol}}^{-1}$ respectively. The molar conductance of ${\mathrm{CH}}_{3}\mathrm{COOH}$ at infinite dilution is. Choose the right option for your answer.

The slope of Arrhenius Plot $(\mathrm{lnk}\text{ v/s }\frac{1}{T})$ of first order reaction is $-5\times {10}^{3}K.$ The value of ${E}_{a}$ of the reaction is. Choose the correct option for your answer. [Given $R=8.314J{K}^{-1}{\mathrm{mol}}^{-1}$]

A particular station of All India Radio, New Delhi, broadcasts on a frequency of $1,368\mathrm{kHz}$ (kilo Hertz). The wavelength of the electromagnetic radiation emitted by the transmitter is [speed of light, $c=3.0\times {10}^{8}{\mathrm{ms}}^{-1}$]