CHEMICAL KINETICS QUIZ-23
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Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything..
Q1.Statement 1: The rate constant of a pseudo unimolecular reaction has the units of a second order reaction
Statement 2: A pseudo unimolecular reaction is a reaction of second order in which one of the reactant is present in large excess
Solution
(d) Both statement and explanation are correct but the reason is different
(d) Both statement and explanation are correct but the reason is different
Q2.Statement 1: k=Ae^(-E_a/RT), the Arrhenius equation represents the dependance of rate constant with temperature
Statement 2: Plot of logk against 1/T is linear and the activation energy can be calculated with this plot
:
Solution
(a) Nacl has fcc structure in which each Na^+ is surrounded by six ions and vic versa.In this octahedral arrangement, coordination, number of bothNa^+ and Cl^- is six for which radius ratio lies between 0.414 and 0.732. The radius ratio does not allow Cl^- ions to touch each other.
(a) Nacl has fcc structure in which each Na^+ is surrounded by six ions and vic versa.In this octahedral arrangement, coordination, number of bothNa^+ and Cl^- is six for which radius ratio lies between 0.414 and 0.732. The radius ratio does not allow Cl^- ions to touch each other.
Q3. Statement 1: In the reaction I_2+2S_2 O_3^(2-)→S_4 O_6^(2-)+2I^-, the two S_2 O_3^(2-) ions are used for every I_2.
Statement 2: The rate of disappearance of I_2 is one half the rate of disappearance of S_2 O_3^(2-)
Solution
(c) Explanation is correct reason for statement.
(c) Explanation is correct reason for statement.
Q4. Statement 1: If the activation energy of a reaction is zero temperature will have no effect on the rate constant. Statement 2: Lower the activation energy faster is the reaction. t that time
Solution
(a) Packing fraction in fcc = 74% Packing fraction in bcc = 67.9%
(a) Packing fraction in fcc = 74% Packing fraction in bcc = 67.9%
Q5.Statement 1: The numerical value of specific rate constant is independent of the concentration of any species present in the reaction mixture
Statement 2: When a reaction is carried out in aqueous solution and some alcohol is added to the reaction mixture, the rate of reaction will not change
Solution
(d) Both statement and explanation are correct but reason for the statement is different
(d) Both statement and explanation are correct but reason for the statement is different
Q6Statement 1: Hydrolysis of ethyl acetate in the presence of acid is a reaction of first order whereas in the presence of alkali, it is a reaction of second order
Statement 2: Acid acts as catalyst only whereas alkali act as one of the reactant
Solution
(a) For fcc, Number of O^(2-) ions =8(corners)×1/8per corner share +6 (faces)×1/2per face share=4 Number of Si^(4+) ions =1/4×OV=1/4×4=1/unit cell Number Fe^(2+) ions =1/4×TV=1/4×8=2/unit cell ⇒Fe_2 SiO_4
(a) For fcc, Number of O^(2-) ions =8(corners)×1/8per corner share +6 (faces)×1/2per face share=4 Number of Si^(4+) ions =1/4×OV=1/4×4=1/unit cell Number Fe^(2+) ions =1/4×TV=1/4×8=2/unit cell ⇒Fe_2 SiO_4
Q7. Statement 1: The rate expression of 2NO_2+F_2⟶2NO_2 F is r=K[NO_2 ][F_2].
Statement 2: The reaction has the mechanism
NO_2+F_2 □(→┴slow ) NO_2 F+F
NO_2+F□(→┴Fast ) NO_2 F
Solution
Q8.Statement 1: According to the transition state theory, for the formation of an activated complex, one of the vibrational degree of freedom is converted into the transition degree of freedom
Statement 2: The energy of the activated complex is higher than the energy of the reactant molecules
Solution
(c) The distance 0.204 nm comes out to be " a⁄√3 " which corresponds to the perpendicular distance between a corner of unit cell and the plane of the three adjacent corners (Fig. III)
(c) The distance 0.204 nm comes out to be " a⁄√3 " which corresponds to the perpendicular distance between a corner of unit cell and the plane of the three adjacent corners (Fig. III)
Q9.Statement 1: Order of reaction can never be fractional for an elementary reaction.
Statement 2: An elementary reaction takes place by one step mechanism.
Solution
(a) AB_2 has bcc structure, A^(2+) possess face centred cubic lattice. B^- ions occupy all the (100%) tetrahedral voids. Thus each A^(2+) is in contact with B^- and each B^- with 4A^(2+) ions.
(a) AB_2 has bcc structure, A^(2+) possess face centred cubic lattice. B^- ions occupy all the (100%) tetrahedral voids. Thus each A^(2+) is in contact with B^- and each B^- with 4A^(2+) ions.
Q10.Statement 1: A catalyst always lower the energy of activation.
Statement 2: The catalyst-reactant interaction forms activated absorbed complex and adsorption is always exothermic.
Solution
(b) All factual statements
(b) All factual statements
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