Question

For a reaction, $r = k(CH_3COCH_3)^{3/2}$ then unit of rate of reaction and rate constant respectively is

• A. $mol\, L^{-1} s^{-1}, mol^{-1/2} L^{1/2} s^{-1}$
• B. $mol^{-1} L^{-1} s^{-1}, mol^{-1/2} L^{-1/2} s^{-1}$
• C. $mol\, L^{-1} s^{-1}, mol^{+1/2} L^{1/2} s^{-1}$
• D. $mol\, L \,s, mol^{+1/2} L^{1/2} s$

Answer 1

Answer: (A)

$Rate =\frac{concentration}{time}=\frac{mol L^{-1}}{s}$
$\quad\quad$= mol L^-1 s^-1
The units of rate constant for the reaction of the nth order = (mol L^-1)^1-n s^-1
here, $n=\frac{3}{2}$
∴ Unit of rate constant = (mol L^-1)^1-3/2 s^-1
$\quad\quad\quad\quad\quad\quad\quad\quad\quad$= (mol L^-1)^-1/2 s^-1
$\quad\quad\quad\quad\quad\quad\quad\quad\quad$= mol^-1/2 L^1/2 s^-1