Question

Rate of formation of SO3 in the following reaction 2SO2 + O2$\rightarrow$2SO3 is 100 g min–1. Hence rate of disappearance of O2 is :

• A. 50 g min-1
• B. 40 g min–1
• C. 200 g min–1
• D. 20 g min–1

Answer 1

Answer: (D)

20 g min–1

Answer 2

$\frac{d}{dt}$ [SO3] = 100 gram / min =$\frac{100}{80}$ mole / min = 1.25

mole/min.

$\frac{- 1}{2}\frac{d}{dt}\left\lbrack SO_{2} \right\rbrack = \frac{- d}{dt} \left\lbrack O_{2} \right\rbrack = \frac{1}{2}\frac{d}{dt}\left\lbrack SO_{3} \right\rbrack$

$\frac{- d}{dt}\frac{1.25}{2}\left\lbrack O_{2} \right\rbrack$= mole/min $= \frac{1.25}{2} \times 32$ gram/min

= 20 gram/min