Home › ISC Class 12 › Chemistry › Chemical Kinetics › A reaction is second order with respect to a rea…
A reaction is second order with respect to a reactant. If the concentration of that reactant is reduced to half, how does the rate change?
ABecomes one-half
BBecomes one-fourth
CRemains unchanged
DBecomes double
Answer & Solution
Correct answer: B. Becomes one-fourth
1. Rate $= k[A]^2$.
2. New rate $= k\left(\tfrac{[A]}{2}\right)^2 = \tfrac{1}{4}k[A]^2$.
3. So the rate becomes one-fourth of the original.
4. Distractor A applies a first order dependence by mistake.
_Source: NCERT Class 12 Chemistry Ch 3 "Chemical Kinetics", p.24_
Related questions
It is observed that for many reactions the rate constant nearly doubles for a rise in tempThe half-life for the radioactive decay of carbon-14 is 5730 years and decay is first ordeIn a pseudo first order reaction, [A]/mol L^-1 reads 0.31 at t = 30 s and 0.17 at t = 60 sIn collision theory, what is meant by the collision frequency (Z)?According to collision theory, in the modified rate expression Rate = P Z_AB e^(-Ea/RT), wHow does a catalyst increase the rate of a chemical reaction?The first order rate constant for decomposition of ethyl iodide is 1.60 x 10^-5 s^-1 at 60The rate constants of a reaction at 500 K and 700 K are 0.02 s^-1 and 0.07 s^-1 respective