For the elementary chemical reaction , identify the correct relationship amongst the rate expression — Reaction Mechanism Chemistry Question
Question
For the elementary chemical reaction $2A(g) \rightarrow B(g) + 3C(g)$, identify the correct relationship amongst the rate expressions.
💡 Solution & Explanation
The rate of a reaction is defined such that it is always a positive quantity. For a balanced equation $aA + bB \rightarrow cC + dD$, the rate is expressed as $-\frac{1}{a}\frac{d[A]}{dt} = -\frac{1}{b}\frac{d[B]}{dt} = \frac{1}{c}\frac{d[C]}{dt} = \frac{1}{d}\frac{d[D]}{dt}$. For $2A \rightarrow B + 3C$, the correct expression divides each derivative by its stoichiometric coefficient, giving $-\frac{1}{2}\frac{d[A]}{dt} = \frac{d[B]}{dt} = \frac{1}{3}\frac{d[C]}{dt}$.