JEE Main · 2008 · 27 Apr 2008 · Offline · Chemical Kinetics

For a reaction

\frac{1}{2} A \to 2 B

, rate of disappearance of '

A

' is related to the rate of appearance of '

B

' by the expression

Answer: (B)

Solution

For

\frac{1}{2} A \to 2 B

each species' rate is its concentration change divided by its stoichiometric coefficient, so the single reaction rate is

\frac{- 1}{1/2} \frac{d [ A ]}{d t} = \frac{1}{2} \frac{d [ B ]}{d t}

. The left side is

- 2 \frac{d [ A ]}{d t}

, and equating this to

\frac{1}{2} \frac{d [ B ]}{d t}

and dividing through gives

- \frac{d [ A ]}{d t} = \frac{1}{4} \frac{d [ B ]}{d t}

JEE Main · 2008 · 27 Apr 2008 · Offline · Single correct option