Physical Chemistry PYQ — Page 22

The $\mathrm{pH}$ of an aqueous solution containing $1M$ benzoic acid $({\mathrm{pK}}_{a}=4.20)$ and $1M$ sodium benzoate is $4.5.$ The volume of benzoic acid solution in $300\mathrm{mL}$ of this buffer solution is __________$\mathrm{mL}$.

Number of spectral lines obtained in ${\mathrm{He}}^{+}$ spectra, when an electron makes transition from fifth excited state to first excited state will be

The molarity of pure water is approximately

We have three aqueous solutions of $\mathrm{NaCl}$ labelled as $‘A’,‘B’$ and $‘C’$ with concentration $0.1M,0.01M$ and $0.001M,$ respectively. The value of van $t’$ Haft factor $(i)$ for these solutions will be in the order.

$9.3g$ of aniline is subjected to reaction with excess of acetic anhydride to prepare acetanilide. The mass of acetanilide produced if the reaction is $100%$ completed is _____$\times {10}^{-1}g$. (Given molar mass in $g{\mathrm{mol}}^{-1}N=14,O=16,C=$$12,H=1)$

The quantity which changes with temperature is:

Choose the Incorrect Statement about Dalton's Atomic Theory

Which out of the following is a correct equation to show change in molar conductivity with respect to concentration for a weak electrolyte, if the symbols carry their usual meaning :

The maximum number of orbitals which can be identified with \(\mathrm{n}=4\) and \(m_l=0\) is ______

In an atom, total number of electrons having quantum numbers \(\mathrm{n}=4,\left|\mathrm{~m}_l\right|=1\) and \(\mathrm{m}_{\mathrm{s}}=-\frac{1}{2}\) is ______

For hydrogen atom, energy of an electron in first excited state is \(-3.4 \mathrm{eV}, \mathrm{K} . \mathrm{E}\). of the same electron of hydrogen atom is \(x \mathrm{eV}\). Value of \(x\) is ______ \(\times 10^{-1} \mathrm{eV}\). (Nearest integer)

The number of moles of methane required to produce \(11 \mathrm{~g} \mathrm{CO}_2(\mathrm{~g})\) after complete combustion is : (Given molar mass of methane in \(\mathrm{g} \mathrm{mol}^{-1}: 16\))

The amount of electricity in Coulomb required for the oxidation of $1\mathrm{mol}$ of ${H}_{2}O$ to ${O}_{2}$ is ______ $\times {10}^{5}C.$

Given below are two statements: Statement-I: The orbitals having same energy are called as degenerate orbitals. Statement-II: In hydrogen atom, $3p$ and $3d$ orbitals are not degenerate orbitals. In the light of the above statements, choose the most appropriate answer from the options given

The number of radial node/s for $3p$ orbital is:

Mass of ethylene glycol (antifreeze) to be added to $18.6\mathrm{kg}$ of water to protect the freezing point at $-24^{\circ}C$ is $\mathrm{kg}$ (Molar mass in ${\mathrm{gmol}}^{-1}$ for ethylene glycol $62,{K}_{f}$ of water $=1.86K\mathrm{kg}{\mathrm{mol}}^{-1}$)

Given below are two statements : Statement I: ${S}_{8}$ solid undergoes disproportionation reaction under alkaline conditions to form ${S}^{2-}$ and ${S}_{2}{O}_{3}^{2-}$ Statement II: ${\mathrm{ClO}}_{4}^{-}$ can undergo disproportionation reaction under acidic condition. In the light of the above statements, choose the most appropriate answer from the options given below:

During Kinetic study of reaction \(2 A+B \rightarrow C+D\), the following results were obtained : \(\begin{array}{llll} & \text { A [M] } & \text { B [M] } & \text { initial rate of formation of D } \\ \text { I } & 0.1 & 0.1 & 6.0 \times 10^{-3} \\ \text { II } & 0.3 & 0.2 & 7.20 \times 10^{-2} \\ \text { III } & 0.3 & 0.4 & 2.88 \times 10^{-1} \\ \text { IV } & 0.4 & 0.1 & 2.40 \times 10^{-2} \\ \end{array}\) Based on above data, overall order of the reaction is ______

For a certain thermochemical reaction $M\rightarrow N$ at $T=400K,{\Delta H}^{o}=77.2\mathrm{kJ}{\mathrm{mol}}^{-1},{\Delta S}^{o}=122{\mathrm{JK}}^{-1}$, $\mathrm{log}$ equilibrium constant $(\mathrm{logK})$ is $-$ _____$\times {10}^{-1}$.

Wavenumber for a radiation having \(5800 Ã…\) wavelength is \(x \times 10 \mathrm{~cm}^{-1}\). The value of \(x\) is ________ (Integer answer)

$r=k[A]$ for a reaction, $50%$ of $A$ is decomposed in $120$ minutes. The time taken for $90%$ decomposition of $A$ is ______ minutes.

Which of the following is strongest Bronsted base?

The reaction; \(\frac{1}{2} \mathrm{H}_{2(\mathrm{~g})}+\mathrm{AgCl}_{(\mathrm{s})} \rightarrow \mathrm{H}_{(\mathrm{aq})}^{+}+\mathrm{Cl}_{(\mathrm{aq})}^{-}+\mathrm{Ag}_{(\mathrm{s})}\) occurs in which of the following galvanic cell :

Which of the following is not correct?