Question

For the reaction: A + 2B $\rightarrow$ 3C + 2D, if rate of disappearance of B is $x \times 10^{-2}$ mol L$^{-1}$ s$^{-1}$, the ratio of rate of reaction to rate of appearance of C is:

• A. 1 : 3
• B. 3 : 1
• C. 1 : 2
• D. 2 : 1

Hint:

Use stoichiometry to relate rates: Rate = $\dfrac{1}{\nu} \dfrac{d[\text{Species}]}{dt}$

Answer 1

The Correct Option is A

Rate of reaction is defined by rate of disappearance of B divided by its stoichiometric coefficient: $r = \dfrac{1}{2} \dfrac{d[B]}{dt}$
Rate of formation of C = $\dfrac{1}{3} \dfrac{d[C]}{dt} \Rightarrow \dfrac{d[C]}{dt} = 3r$
So, ratio of rate of reaction to appearance of C = $r : 3r = 1 : 3$