**Practice Problem 4**

Calculate the rate at which HI disappears in the following reaction at the moment when
I_{2} is being formed at a rate of 1.8 x 10^{-6} moles per liter per
second:

2 HI(*g*) H_{2}(*g*) + I_{2}(*g*)

**Answer**

3.6 x 10^{-6} *M*/s