Chemistry Question Bank

In a reaction 2HI ⟶ H2 + I2, the concentration of HI decreases from 0.5 mol L–1 to 0.4 mol L–1 in 10 minutes. What is the overall rate of reaction during this interval?

Consider the reaction, 2N O 4NO O . -> In the reaction NO2 is being formed at the rate of 0.0125 mol L–1 s–1. What is the rate of reaction at this time?

Chemical kinetics plays an important role in

Assertion (A): The order of a reaction can have fractional value. Reason (R): The order of a reaction cannot be written from balanced equation of a reaction.

Assertion (A): In rate law, unlike in the expression for equilibrium constants, the exponents for concentrations do not necessarily match the stoichiometric coefficients. Reason (R): It is the mechanism and not the ba…

Choose the correct answer out of the following choices. Assertion (A): Most people think diamond is forever. Reason (R): Conversion rate of diamond to graphite is very low.

Collision theory is used to explain how chemical species undergo a reaction. Using this theory and the kinetic molecular model, which of the following does NOT influence the rate of a chemical reaction?

For a first order reaction A P, the temperature (T) dependent rate constant (k) was found to follow the equation 1 logk 6.0 T . The pre- exponential factor A and the activation energy Ea, respectively are: (a) 1.0…

An endothermic reaction with high activation energy for the forward reaction is given by the diagram : (a) (b) (c) E E (d)

The potential energy diagram for a reaction R P -> is given below o H of the reaction corresponds to the energy:

Ea and H values of reactions R1, R2, R3 and R4 carried out at the same temperature are as given below: R1 Ea = 40 kJ mol–1, H = – 80 kJ mol–1 R2 Ea = 20 kJ mol–1, H = – 30 kJ mol–1 R3 Ea = 60 kJ mol–1, H = + 40 kJ mol…

The first order rate constant for a certain reaction increases from 1.667 × 10–6 s–1 at 727ºC to1.667 × 10–4 s–1 at 1571ºC. The rate constant at 1150ºC, assuming constancy of activation energy over the given temperatu…

In most cases, for a rise of 10K temperature the rate constant is doubled to tripled. This is due to the reason that (a)collision frequency increases by a factor of 2 to 3. (b)fraction of molecules possessing threshol…

For a certain reaction A -> products, the t1/2 as a function of [A]0 is given as below: [A]0 (M) : 0.1 0.025 t1/2 (min) : 100 Which of the following is/are true ?

The reaction of hydrogen and iodine monochloride is given as: H g 2ICl g 2HCl g I g -> The reaction is of first order with respect to H2 (g) and ICl(g), following mechanisms were proposed. Mechanism A: H g 2…

A first order reaction has a specific reaction rate of 10– 2 sec–1. How much time will it take for 20g of the reactant to reduce to 5 g? (NEET 2017)

A first order reaction is 50% completed in 1.26 10 x s. How much time would it take for 100% completion? (JIPMER 2017) (a) 1.26 10 s x (b) 2.52 10 s x (c) 2.52 10 s x

The rate of a first-order reaction is 0.04 mol L s at 10 seconds and 0.03 mol L s at 20 seconds after initiation of the reaction. The half-life period of the reaction is. (NEET 2016)

Which one of the following statements for the order of a reaction is incorrect? (AIPMT 2011)

The unit of rate constant for a zero-order reaction is. (AIPMT 2011 M)

The half-life of a substance in a certain enzyme- catalysed reaction is 138 s. The time required for the concentration of the substance to fall from 1.28 mg L– 1 to 0.04 mg L–1 is (AIPMT 2011)

The rate law for the reaction, xA yB mP nQ -> is rate = . c d k A B What is the total order of the reaction? (Kerala CEE 2011)

For the reaction [N2O5(g) -> 2NO2(g) + 1/2 O2(g)] the value of rate of disappearance of N2O5 is given as 6.25 × l0–3 mol L–1 s–1 The rate of formation of NO2 and O2 is given respectively as: (AIPMT 2010)

For an endothermic reaction, energy of activation is Ea and enthalpy of reaction of H (both of these in kJ/mol). Minimum value of Ea will be. (AIPMT 2010)

For the reaction, N2 + 3H2 -> 2NH3, d NH dt = 2 x 10–4 mol L–1 s–1, the value of d H dt would be: (AIPMT 2009)