Question

The decomposition of dimethyl ether is a fractional order reaction. The rate of reaction is given by rate $=k\left(p_{CH_3OCH_3}\right)^{3 /2}$. If the pressure is measured in bar and time in minutes, then what are the units of rate and rate constant?

• A. bar $min^{-1}$, $bar^{2} min^{-1}$
• B. bar $min^{-1}$, $bar^{-1/2} min^{-1}$
• C. $bar^{-1/2} min^{-1}$, $bar^{2} min^{-1}$
• D. $bar\, min^{-1}$, $bar^{1/2} min^{-1}$

Answer 1

Answer: (B)

In terms of pressure,
Rate $= k\left(p_{CH_3OCH_3}\right)^{3 /2}$
Unit of rate = bar $min^{-1}$
Unit of rate constant $=\frac{rate}{\left(p_{CH_3OCH_3}\right)^{3 /2}}$
$=\frac{bar\,min^{-1}}{bar^{3 /2}}$
$=bar^{-1 /2} min^{-1}$