Kinetics - Nuclear - Surface - Photochemistry - Chemistry MCQ

If 0.001M of a substance quenches the efficiency of fluorescence by 20%, the value of Stern-Volmer constant in M^-1 is      

Decomposition of ammonia on tungsten at 850^oC has a rate constant value of 0.10 Torr sec^-1. If the initial pressure of ammonia is 100 Torr, the pressure of ammonia at t = 200 sec is     

The value of the rate constant for the gas phase reaction, 2NO₂ + F₂ → 2NO₂F  is 38 dm³ mol^–1 s^–1 at 300 K. The order of the reaction is:    

A reaction follows second order rate law, 

The specific rate constant of decomposition of a compound is represented by​

The activation energy of decomposition for this compound at 300 K is:           

The fluorescence life time of a molecule in solution is 10 ns. If the fluorescence quantum yield is 0.1, the rate constant of fluorescence decay is:    

For the reaction shown below,

The value of k₁ is 1 × 10^–4 s^–1. If the reaction starts from X, the ratio of the concentrations of Y and Z at any given time during the course of the reaction is found to be  The value of k₂ is:

For an adsorbant-adsorbate system obeying the Langmuir adsorption isotherm, K = 0.48 bar^-1 and P = 0.16 bar^-1. At what pressure will 50% of the surface be covered?             

The reaction, 2NO(g) + O₂(g)  → 2NO₂(O)  proceeds via the following steps:  
   
The rate of this reaction is equal to    

The decomposition of N₂O₅ according to following reaction is first order             
2 N₂O₅ → 4 NO₂(g) + O₂ (g). After 30 minutes from the start of decomposition in a closed vessel the total pressure developed is found to be 250 mm of Hg and on complete decomposition the total pressure is 500 mm of Hg. Calculate rate constant of the reaction.    

1 g of ⁹⁰Sr gets converted to 0.953 g after 2 yr. The half-life of 90Sr, and the amount of ⁹⁰Sr remaining after 5 yr are:    

A graph is plotted between log10K and 1/T in which straight line BC has no slope and tan(ᴓ) = -1/2.303 and intercept on y-axis is 5. What is activation energy?    

In a reaction, A + B → Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (Aand B) are doubled, rate law for the reaction can be written as

 when the rate of the reaction is equal to the rate constant, the order of the reaction is

The inversion of cane sugar proceeds with half-life of 500 minutes at pH 5 for any concentration of sugar. However if pH = 6, the half-life changes to 50 minute. The rate law expression for the sugar inversion can be written as:

The reaction, A(g) + 2B(g) → C(g) + D(g) is an elementary process. In an experiment, the initial partial pressure of A and B are P_A = 0.60 and P_B = 0.80 atm. When P_C = 0.2 atm the rate of reaction relative to the initial rate is:    

For an enzyme catalyzed reaction, a Lineweaver-Burk plot gave the slope value = 40 s and intercept = 4 (mmoldm^-3s^-1)^-1. If initial concentration of enzyme is 2.5× 10^-9 moldm^-3, catalytic efficiency is 10^x. Calculate the value of ‘x’.           

At 273 K, N₂ is adsorbed on mica surface. A plot of 1/V vs 1/P (V in m³ and P in Torr) gives a straight line with slope equal to 2.0 × 10^–5 torr m^–3 and an intercept V_m equal to 4 × 10^–8 m³. The adsorption coefficient and number of molecules of N₂ forming monolayer, resp., are:

Physiosorbed particles undergo desorption at 27⁰C with an activation energy of 16.628 kJ/mol. Assuming first order process and a frequency factor of 10¹² Hz, the average residence time (in sec) of particles on the surface is

A monoatomic gas, X absorbed on a surface, Langmuir, A plot of the fraction of surface coverage, q against the concentration of the gas [X], for very low concentration of the gas, is described by the equation: 

Which of the following transformations is not correct?

Which ones of the following reactions are artificial radioactive decay?

A, B, C and D elements form compounds AC, A₂D and BD. If AC and A₂D are radioactive and BD is not radioactive compound, find the following radioactive compounds-           
(I) A₂                                       (II) A₂C                          (III) C₂D                        (IV) BC           

A substance absorbs 2.0 x 10¹⁶ quanta or radiations per second and 0.002 mole of it reacts in 1200 seconds. What is the quantum yield or the reaction (N = 6.02 x 10²³)?           

Which regions of the light radiations of the visible ultraviolet lying between – wavelength are chiefly concerned in bringing about photochemical reactions?           

A closed vessel with rigid walls contain 1 mol of ₉₂U²³⁸ and 1 mol of air at 298K. Considering complete decay of ₉₂U²³⁸ to ₈₂U²⁰⁶, the ratio of the final pressure to the initial pressure of the system at 298K is____?           

The periodic table consists of 18 groups. An isotope of copper, on bombardment with protons, undergoes a nuclear reaction yielding element X as shown below. To which group, element X belongs in periodic table? ₂₉Cu⁶³ + ₁H¹ → X + 2 ₁H¹ + α + 6 ₀n¹