Advertisements
Advertisements
प्रश्न
With the help of an example explain what is meant by pseudo first order reaction.
उत्तर
Pseudo first order reaction: Reaction which appears to be a second order reaction, but actually is first order reaction is called pseudo first order reaction. This condition occurs in a chemical reaction between two substances when one reactant is present in large amount. The concentration of reactant present in excess does not gat alterned much during the course of the reaction. Due to this reaction behaves as first order reaction.
E.g. hydrolysis of esters
\[\ce{CH3COOC2H5 + H2O -> CH3COOH + C2H5OH}\]
Rate law for this reaction is; rate = \[\ce{k[CH3COOC2H5]][H2O]}\]
But the concentration of water does not change during the course of the reaction. So; \[\ce{H2O}\] is constant.
Therefore rate = \[\ce{k1[CH3COOC2H5]}\], where \[\ce{k = k[H2O]}\].
The reaction behaves as a first order reaction.
APPEARS IN
संबंधित प्रश्न
Sucrose decomposes in acid solution into glucose and fructose according to the first order rate law with `"t"_(1/2)`= 3 hours. What fraction of the sample of sucrose remains after 8 hours?
Time required to decompose SO2Cl2 to half of its initial amount is 60 minutes. If the decomposition is a first order reaction, calculate the rate constant of the reaction.
The rate constant for a first order reaction is 60 s−1. How much time will it take to reduce the initial concentration of the reactant to its `1/16`th value?
For the decomposition of azoisopropane to hexane and nitrogen at 543 K, the following data are obtained.
| t (sec) | P(mm of Hg) |
| 0 | 35.0 |
| 360 | 54.0 |
| 720 | 63.0 |
Calculate the rate constant.
Show that the time required for 99.9% completion of a first-order reaction is three times the time required for 90% completion.
The decomposition of formic acid on gold surface follows first-order kinetics. If the rate constant at 300 K is 1.0 × 10−3 s−1 and the activation energy Ea = 11.488 kJ mol−1, the rate constant at 200 K is ______ × 10−5 s−1. (Round off to the Nearest Integer)
(Given R = 8.314 J mol−1 K−1)
A definite volume of H2O2 undergoing spontaneous decomposition required 22.8 c.c. of standard permanganate solution for titration. After 10 and 20 minutes respectively the volumes of permanganate required were 13.8 and 8.25 c.c. The time required for the decomposition to be half completed is ______ min.
The slope in the plot of `log ["R"]_0/(["R"])` Vs. time for a first-order reaction is ______.
How will you represent first order reactions graphically?
Write the equation for integrated rate law for a first order reaction.
