JEE Main Chemistry — Physical Chemistry previous year questions with solutions.
The number of following statement/s which is/are incorrect is ______ A) Line emission spectra are used to study the electronic structure B) The emission spectra of atoms in the gas phase show a continuous spread of wavelength from red to violet. C) An absorption spectrum is like the photographic negative of an emission spectrum D) The element helium was discovered in the sun by spectroscopic method
It is observed that characteristic X-ray spectra of elements show regularity. When frequency to the power 'n' i.e. ${v}^{n}$ of X-rays emitted is plotted against atomic number $Z$, the following graph is obtained.  The value of 'n' is
The number of given orbitals which have electron density along the axis is ${p}_{x},{p}_{y},{p}_{z},{d}_{\mathrm{xy}},{d}_{\mathrm{yz}},{d}_{\mathrm{xz}},{d}_{z}^{2},{d}_{{x}^{2}-{y}^{2}}$
Consider the following reaction approaching equilibrium at $27^{\circ}C$ and $1$ atm pressure $A+B\underset{{K}_{r}={10}^{2}}{\overset{{K}_{t}={0}^{3}}{\rightleftharpoons }}C+D$ The standard Gibb's energy change $({\Delta }_{r}G^{\circ})$ at $27^{\circ}C$ is $(-)$ _____ ${\mathrm{kJmol}}^{-1}$ (Nearest integer). (Given : $R=8.3J{K}^{-1}{\mathrm{mol}}^{-1}$ and $\mathrm{ln}10=2.3$)
The solubility product of ${\mathrm{BaSO}}_{4}$ is $1\times {10}^{-10}$ at $298K$. The solubility of ${\mathrm{BaSO}}_{4}$ in $0.1M{K}_{2}{\mathrm{SO}}_{4}(\mathrm{aq})$ solution is ------$\times {10}^{-9}g{L}^{-1}$(nearest integer). Given: Molar mass of ${\mathrm{BaSO}}_{4}$ is $233g{\mathrm{mol}}^{-1}$
The total number of isoelectronic species from the given set is ________. ${O}^{2-},{F}^{–},\mathrm{Al},{\mathrm{Mg}}^{2+},{\mathrm{Na}}^{+},{O}^{+},\mathrm{Mg},{\mathrm{Al}}^{3+},F$
$5g\mathrm{of}\mathrm{NaOH}$ was dissolved in deionized water to prepare a $450\mathrm{mL}$ stock solution. What volume (in mL) of this solution would be required to prepare $500\mathrm{mL}$ of $0.1M$ solution ? Given : Molar Mass of $\mathrm{Na},O\mathrm{and}H\mathrm{is}23,16\mathrm{and}1g{\mathrm{mol}}^{–1}$ respectively
Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R Assertion A : $5f$ electron can participate in bonding to a far greater extent than $4f$ electrons Reason R : $5f$ orbitals are not as buried as $4f$ orbitals In the light of the above statements, choose the correct answer from the options given below
One mole of an ideal gas at $350K$ is in a $2.0L$ vessel of thermally conducting walls, which are in contact with the surroundings. It undergoes isothermal reversible expansion from $2.0L$ to $3.0L$ against a constant pressure of $4\mathrm{atm}$. The change in entropy of the surroundings $(\Delta S)$ is _____ $J{K}^{–1}$ (Nearest integer) Given: $R=8.314J{K}^{-1}{\mathrm{mol}}^{-1}$.
The volume of $0.02M$ aqueous $\mathrm{HBr}$ required to neutralize $10.0\mathrm{mL}$ of $0.01M$ aqueous $\mathrm{Ba}(\mathrm{OH}{)}_{2}$ is (Assume complete neutralization)
Given below are two statements: Statement-I : Methyl orange is a weak acid. Statement-II : The benzenoid form of methyl orange is more intense/deeply coloured than the quinonoid form. In the light of the above statement, choose the most appropriate answer from the options given below:
The dissociation constant of acetic is $x\times {10}^{–5}$. When $25\mathrm{mL}\mathrm{of}0.2M{\mathrm{CH}}_{3}\mathrm{COONa}$ solution is mixed with $25\mathrm{mL}\mathrm{of}0.02M{\mathrm{CH}}_{3}\mathrm{COOH}$ solution, the $\mathrm{pH}$ of the resultant solution is found to be equal to $5$. The value of $x$ is _______.
The total change in the oxidation state of manganese involved in the reaction of ${\mathrm{KMnO}}_{4}$ and potassium iodide in the acidic medium is ________.
Henry Moseley studied characteristic $X$-ray spectra of elements. The graph which represents his observation correctly is Given $v=$ Frequency of X-ray emitted $Z=$ Atomic number
The osmotic pressure of solutions of PVC in cyclohexanone at $300K$ are plotted on the graph. The molar mass of PVC is $g{\mathrm{mol}}^{-1}$ (Nearest integer)  (Given : $R=0.083L\mathrm{atm}{K}^{-1}{\mathrm{mol}}^{-1}$ )
The wavelength of an electron of kinetic energy $4.50\times {10}^{-29}J$ is $________\times 10–5m.$ (Nearest integer) Given: mass of electron is$9\times 10–31\mathrm{kg},h=6.6\times 10–34\mathrm{Js}$
The number of correct statement/s from the following is _____ . A.Larger the activation energy, smaller is the value of the rate constant. B. The higher is the activation energy, higher is the value of the temperature coefficient. C. At lower temperatures, increase in temperature causes more change in the value of $k$ than at higher temperature. D. A plot of $\mathrm{ln}k$ vs $\frac{1}{T}$ is a straight line with slope equal to $-\frac{\mathrm{Ea}}{R}$
The logarithm of equilibrium constant for the reaction ${\mathrm{Pd}}^{2+}+4{\mathrm{Cl}}^{-}\rightleftharpoons {\mathrm{PdCl}}_{4}^{2-}$ is (Nearest integer) Given: $\frac{2.303\mathrm{RT}}{F}=0.06V$ ${\mathrm{Pd}}_{(\mathrm{aq})}^{2+}+2{e}^{-}\rightleftharpoons \mathrm{Pd}(s){E}^{o}=0.83V$ ${\mathrm{PdCl}}_{4}^{2-}(\mathrm{aq})+2{e}^{-}\rightleftharpoons \mathrm{Pd}(s)+4{\mathrm{Cl}}^{-}(\mathrm{aq})$ ${E}^{o}=0.65V$
In an electrochemical reaction of lead, at standard temperature, if ${E}_{({\mathrm{Pb}}^{2+}/\mathrm{Pb})}^{o}=m\text{ Volt }$and ${E}_{({\mathrm{Pb}}^{4+}/\mathrm{Pb})}^{o}=n\mathrm{Volt},$then the value of $E^{\circ}({\mathrm{Pb}}^{2+}/{\mathrm{Pb}}^{4+})$ is given by $m–\mathrm{xn}$. The value of x is _______. (Nearest integer)
Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride. The volume of hydrogen gas produced at STP from the reaction of $11.5g$ of zinc with excess $\mathrm{HCl}$ is $L$ (Nearest integer) (Given : Molar mass of $\mathrm{Zn}$ is $65.4g{\mathrm{mol}}^{-1}$ and Molar volume of ${H}_{2}$ at $\mathrm{STP}=22.7L$ )
The enthalpy change for the adsorption process and micelle formation respectively are
Electrons in a cathode ray tube have been emitted with a velocity of $1000{\mathrm{ms}}^{-1}$. The number of following statements which is/are true about the emitted radiation is Given : $h=6\times {10}^{-34}\mathrm{Js},{m}_{e}=9\times {10}^{-31}\mathrm{kg}$ (A ) The deBroglie wavelength of the electron emitted is $666.67\mathrm{nm}$ (B ) The characteristic of electrons emitted depend upon the material of the electrodes of the cathode ray tube. (C) The cathode rays start from cathode and move towards anode. (D ) The nature of the emitted electrons depends on the nature of the gas present in cathode ray tube..
At $298K$, a $1$ litre solution containing $10\mathrm{mmol}$ of ${\mathrm{Cr}}_{2}{O}_{7}^{2-}$ and $100\mathrm{mmol}$ of ${\mathrm{Cr}}^{3+}$ shows a $\mathrm{pH}$ of $3.0$. Given : ${\mathrm{Cr}}_{2}{O}_{7}\rightarrow 2-{\mathrm{Cr}}^{3+};{E}^{0}=1.330V$ and $\frac{2.303\mathrm{RT}}{F}=0.059V$ The potential for the half cell reaction is $x\times {10}^{-3}V$ . The value of $x$ is _____ .
For lead storage battery pick the correct statements A. During charging of battery, ${\mathrm{PbSO}}_{4}$ on anode is converted into ${\mathrm{PbO}}_{2}$ B. During charging of battery, ${\mathrm{PbSO}}_{4}$ on cathode is converted into ${\mathrm{PbO}}_{2}$ C. Lead storage battery consists of grid of lead packed with ${\mathrm{PbO}}_{2}$ as anode D. Lead storage battery has $~38%$ solution of sulphuric acid as an electrolyte Choose the correct answer from the options given below: