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प्रश्न
What is pseudo first order reaction? Give one· example of it.
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उत्तर
A reaction which has higher order true rate law but experimentally found to behave as first order are called pseudo first order reaction.
e.g. `C_12H_22O_(11(aq))+H_2OrarrC_6H_12O_6+C_6H_12O_6`
Sucrose Glucose fractose
is an example of pseudo first order reaction, because water takes part in the reaction the true rate law
rate = k'[C12H22O11][H2O]
indicates that the reaction must be second order. Similarly to the hydrolysis of ester,[H2O] is constant and
the rate law became
rate=k[C12H22O11]
Thus, the second order true law is converted, to first order rate law.
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संबंधित प्रश्न
Define “zero order reaction”.
A reaction is second order in A and first order in B.
(i) Write the differential rate equation.
(ii) How is the rate affected on increasing the concentration of A three times?
(iii) How is the rate affected when the concentrations of both A and B are doubled?
For the hydrolysis of methyl acetate in aqueous solution, the following results were obtained :
| t/s | 0 | 30 | 60 |
| [CH3COOCH3] / mol L–1 | 0.60 | 0.30 | 0.15 |
(i) Show that it follows pseudo first order reaction, as the concentration of water remains constant.
(ii) Calculate the average rate of reaction between the time interval 30 to 60 seconds.
(Given log 2 = 0.3010, log 4 = 0.6021)
For a reaction, \[\ce{A + B -> Product}\]; the rate law is given by, `r = k[A]^(1/2)[B]^2`. What is the order of the reaction?
The conversion of molecules X to Y follows second order kinetics. If concentration of X is increased to three times how will it affect the rate of formation of Y?
From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.
\[\ce{3NO_{(g)} -> N2O_{(g)}}\] Rate = k[NO]2
From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.
\[\ce{H2O2_{( aq)} + 3I^-_{( aq)} + 2H^+ -> 2H2O_{(l)} + I^-_3}\] Rate = k[H2O2][I−]
From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.
\[\ce{C2H5Cl_{(g)} -> C2H4_{(g)} + HCl_{(g)}}\] Rate = k [C2H5Cl]
A reaction is first order in A and second order in B. How is the rate affected on increasing the concentration of B three times?
For a reaction R ---> P, half-life (t1/2) is observed to be independent of the initial concentration of reactants. What is the order of reaction?
How does calcination differ from roasting?
Rate of reaction for the combustion of propane is equal to:
\[\ce{C3H8_{(g)} + 5O2_{(g)} -> 3CO2_{(g)} + 4H2O_{(g)}}\]
Rate law for the reaction \[\ce{A + 2B -> C}\] is found to be Rate = k [A][B]. Concentration of reactant ‘B’ is doubled, keeping the concentration of ‘A’ constant, the value of rate constant will be ______.
The value of rate constant of a pseudo first order reaction ______.
For which type of reactions, order and molecularity have the same value?
Why is the probability of reaction with molecularity higher than three very rare?
Assertion: The enthalpy of reaction remains constant in the presence of a catalyst.
Reason: A catalyst participating in the reaction, forms different activated complex and lowers down the activation energy but the difference in energy of reactant and product remains the same.
Assertion: Rate constants determined from Arrhenius equation are fairly accurate for simple as well as complex molecules.
Reason: Reactant molecules undergo chemical change irrespective of their orientation during collision.
The role of a catalyst is to change
For a reaction \[\ce{Cl2l(g) + 2No(g) -> 2NaCl(g)}\] the rate law is expressed as rate= K[Cl2] [No]2 what is the order of the reaction?
The rate of a chemical reaction double for every 10° rise in temperature. If the temperature is raised. by 50°C, the rate of relation by about:-
If the 0.05 molar solution of m+ is replaced by a 0.0025 molar m+ solution, then the magnitude of the cell potential would be
The following data was obtained for chemical reaction given below at 975 K.
\[\ce{2NO(g) + 2H2(g) -> N2(g) + 2H2O(g)}\]
| [NO] | [H2] | Rate | |
| Mol L-1 | Mol L-1 | Mol L-1 s-1 | |
| (1) | 8 × 10-5 | 8 × 10-5 | 7 × 10-9 |
| (2) | 24 × 10-5 | 8 × 10-5 | 2.1 × 10-8 |
| (3) | 24 × 10-5 | 32 × 10-5 | 8.4 × 10-8 |
The order of the reaction with respect to NO is ______. (Integer answer)
For a chemical reaction starting with some initial concentration of reactant At as a function of time (t) is given by the equation,
`1/("A"_"t"^4) = 2 + 1.5 xx 10^-3` t
The rate of disappearance of [A] is ____ × 10-2 M/sec when [A] = 2 M.
[Given: [At] in M and t in sec.]
[Express your answer in terms of 10-2 M /s]
[Round off your answer if required]
Assertion (A): Order of reaction is applicable to elementary as well as complex reactions.
Reason (R): For a complex reaction, molecularity has no meaning.
