List of top Chemistry Questions

The time required (in hours) to reduce 3 mol of $ Fe^{3+} $ ions to $ Fe^{2+} $ ions with 2.0 amperes of current is (1 F = 96500 C mol$^{-1} $)

Molar conductivities at infinite dilution $ \Lambda_m^\circ $ for $ Ba(OH)_2 $, $ BaCl_2 $ and $ NH_4Cl $ are 457.6, 240.6 and 213.0 $ S cm^2 mol^{-1} $ respectively. The $ \Lambda_m^\circ $ for ammonium hydroxide (in $ S cm^2 mol^{-1} $) is

Which one of the following has the highest molar conductivity?

The minimum voltage (in V) required to bring about the electrolysis of 1M copper (II) sulphate solution at 298 K is (Given E$^\circ_{Cu^{2+}/Cu}$ = 0.34V and E$^\circ_{H_2O/H^+}$ = -1.23V)

Observe the following half cell reactions and choose the correct options
(I) 2H2O(l) → O2(g)+4H+ +4e− E0 = 1.23V
(II) H+(aq) + e− → 1/2 H2(g) E0 = 0.00V
(III) 2SO4^2− (aq) → S2O8^2− (aq)+2e− E0 = −1.96V
(a) In dilute H2SO4 solution, H+ ions are reduced at cathode.
(b) In concentrated H2SO4 solution, water is oxidized at anode.
(c) In dilute H2SO4 solution, water is oxidized at anode.
(d) In dilute H2SO4 solution, SO4^2− ions are oxidized at anode.

For an adiabatic change in a system, the condition which is applicable is

The isotherms of an ideal gas at $ T_1, T_2, T_3 $ along with their slopes (m) (in the brackets) are shown here. If $ T_1 > T_2 > T_3 $, then the correct order of slopes of these isotherms is:

If the standard enthalpy of sublimation $ (\Delta_{sub}H^\circ) $ of solid $ CO_2 $, naphthalene, Li and Na are 25.2, 73.0, 162, 108 kJ mol$^{-1} $ respectively, the order of sublimation of these substances with temperature is

Identify the correct statements from the following
(A) The compressibility factor (Z) for an ideal gas is 1
(B) Uranium isotopes ($ ^{235}U $ and $ ^{238}U $) are separated by converting them into $ UF_6 $ vapours
(C) Decrease in temperature increases the kinetic energy of gas molecules

Which of the following reaction is not feasible?

Given below are two statements Assertion (A): The enthalpy of formation of graphite is taken as zero. Reason (R): Graphite is thermodynamically most stable allotrope of carbon. The correct answer is

If $ \Delta G $ and $ \Delta S $ for the reaction $ A(g) \to B(g) + 2C(g) $ at 2000 K are -40 kJ mol$^{-1}$ and 0.22 kJ K$^{-1}$ mol$^{-1}$, respectively, the change in internal energy for the same reaction approximately (in kJ mol$^{-1}$) is?

If 100 L of an ideal gas at a pressure of 2 atm is compressed isothermally and reversibly to a final volume of ‘X’ L releases -460.6 L atm heat, the final volume ‘X’ (in L) is

11.0 L of an ideal gas at constant external pressure of 5 atm is compressed isothermally to a final volume of one liter. The heat absorbed and work done respectively, during this compression (in L atm) are

Which one of the following options is correct for \[ q = -ve, \, w = +ve \{ (where $q$ and $w$ are heat and work respectively)} \]

If the enthalpy and entropy change for a reaction at 298 K are -145 kJ mol$^{-1}$ and -650 J K$^{-1}$ mol$^{-1}$ respectively, which one of the following statements is correct?

For 1 mol of gas, the plot of pV vs. p is shown below. p is the pressure and V is the volume of the gas. What is the value of compressibility factor at point A?

A solution is prepared by adding 2 g of X” to 1 moIe of water. Mass percent of “X” in the solution is

One mole of P₄ reacts with 8 moles of SOCI₂ to give 4 moles of A. x mole of SO₂ and 2 moles of B. A, B and x respectively are

When 3 moles of gas A is mixed with 1 mole of gas B at room temperature and 1 atm pressure, the entropy of mixing is
(Given log 3=0.4771,
log 4 = 0.6020)

Calculate the number of moles of carbon mono oxide in the following reaction
CH₃CH₂CHO $\stackrel{hv}{→}$ CH₃CH₃ + CO
If the light irradiated has λ= 3020 A°, the quantum yield of reaction 0.54 and the light energy absorbed is 15000 erg in a given time.

Which of the following is more reliable?

Calculate the mass of urea $(NH_2CONH_2)$ required in making 2.5 kg of 0.25 molal aqueous solution.

An element with molar mass $2.7 \times 10^{-2}$ kg/mol forms a cubic unit cell of edge length 405pm. If the density is $2.7 \times 10^3$ kg/$m^3$. The nature of the cell is?

The value of Avogardro's Number is ______