List of top Physical Chemistry Questions

The value of R in energy of activation is

Which among the following cations has the lowest molar ionic conductivity in water at infinite dilution and at 25 degree centigrade?

When one of the reactants is present in such great excess that its concentration may be considered constant or nearly so, the reaction is said to be of___

The longest wavelength of light absorbed by a hydrogen-like atom is 2.48 nm. The nuclear charge (Z) of the atom is ........
(Round off to nearest integer) (Rydberg constant $ R_{\infty} = 109700 \, \text{cm}^{-1} $)

Fullerene (C₆₀) crystallizes in an FCC unit cell (edge length = 14.14 Å) with one C₆₀ centered at each lattice point. The smallest distance (in Å) between the centers of two C₆₀ molecules is ..........
(Round off to two decimal places)

A film of stearic acid partially covers the water surface in a container. The work needed to decrease this coverage by 1 cm² is 25.0 × 10⁻⁷ J. The surface tension (in N/m) of the film is .......
(Round off to three decimal places)
(Surface tension of pure water is 0.072 N/m)

The heat of formation of MgO at 300 K and 1 bar pressure is -600.60 kJ mol$^{-1}$. The free energy (in kJ mol$^{-1}$) of formation of MgO at 280 K is ......... (Round off to nearest integer)

Sea water containing 1 M NaCl has to be desalinated at 300 K using a membrane permeable only to water. The minimum pressure (in bars) required on the sea-water side of the membrane is ......... (Round off to one decimal place)

A bacterial colony grows via cell division where each mother bacterium independently produces two daughter cells in 20 minutes. If the concentration of bacteria is $ 10^4 \, \text{cm}^{-3} $, the colony becomes harmful. Starting from a colony with an initial concentration of 5 cm$^{-3}$, the time taken (in minutes) for the colony to become harmful is ......... (Round off to nearest integer)

The Maxwell distribution of speeds of a gas at 300 K is given below. The molar mass (in g mol$^{-1}$) of this gas is ......... (Round off to one decimal place) (R = 8.3 J mol$^{-1}$ K$^{-1}$)

At a certain wavelength, liquid P transmits 70%, whereas liquid Q transmits 30% of the incident light when separately placed in a spectrophotometric cell (path length = 1 cm). In a binary mixture of liquids P and Q (assume non-interacting liquids), the absorbance in the same cell is 0.25. The volume fraction of liquid P in the binary mixture is .......... (Round off to two decimal places)

The mean ionic activity coefficient for a 0.01 M aqueous solution of Ca$_3$(PO$_4$)$_2$ is .......... (Round off to three decimal places) (Given: $ \log_{10} \gamma_{\pm} = -0.509 Z_{\pm}^2 \sqrt{T} $)

For the reaction, CuSO$_4$ (aq) + Zn (s) → ZnSO$_4$ (aq) + Cu (s), the value of $ \Delta G^\circ $ (in kJ mol$^{-1}$) is .......... (Round off to the nearest integer) (Reduction potential: Cu$^{2+}$(aq)/Cu(s) = +0.34 V; Zn$^{2+}$(aq)/Zn(s) = -0.76 V))

The compound(s) which will have only two signals in the $ ^1 \text{H} $ NMR spectrum in 3:2 ratio is(are)

The boron adduct(s), which show(s) three signals in $ ^1 \text{H} $ NMR spectrum with the intensity ratio 1:2:3 is(are)

In water, the enthalpy of a protein in its folded state ($H_f$) is lower than that in its unfolded state ($H_{UF}$). The entropies of the folded and unfolded states are $S_f$ and $S_{UF}$, respectively. The condition(s) under which this protein spontaneously folds in water at a temperature $T$, is(are)

$\psi(x,y,z)$ describes the wavefunction of a particle. The probability of finding the particle between $x$ and $x+dx$, $y$ and $y+dy$, and $z$ and $z+dz$, can be expressed as

For the reaction shown in Scheme 1, the concentration profiles of different species are provided.
$\text{Scheme 1:}$

Based on this graph, the correct condition(s) regarding the rate constants is(are)

The solid state structure of HF is

The number of non-bonding electrons present in the frontier molecular orbitals of HF is

The Boyle temperature ($T_B$) is defined as the temperature at which the properties of a real gas coincide with those of an ideal gas in the low pressure limit. The graph that shows the pressure dependence of the compression factor (Z) for a real gas at $T_B$ is

The force constant for H$^{35}$Cl and D$^{35}$Cl are the same and both can be considered as harmonic oscillators. H$^{35}$Cl has a fundamental vibrational transition at 2886 cm$^{-1}$. The ratio of the zero-point energy of H$^{35}$Cl to that of D$^{35}$Cl is

At constant pressure, the $\mu$ – T diagram for a pure substance that sublimes (s = solid, l = liquid and g = gas) is

The correct order of boiling points of compounds I–IV is

The graph that represents the temperature (T) – entropy (S) variation of a Carnot cycle is