Ta có: \({CM_{{{\left( {{I_2}} \right)}}}} = 0,0198M.\)
Gọi nồng độ iot chuyển hóa là x.
\(\eqalign{
& \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,{I_2}\left( k \right)\,\,\, \;\;\;\;\mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over
{\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}}\;\;\; \,\,2I\left( k \right) \cr
& \text{Phản ứng}:\,\,\,\,\,\,\,x \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\;\;\;\;\;\;\;2x\cr
& \text{Cân bằng}:\,\,\,\,0,0198 - x\,\,\,\,\,\,\,\,\,2x \cr} \)
Ta có: \({{4{x^2}} \over {0,0198 - x}} = 3,{8.10^{ - 5}} \Rightarrow x \approx 0,{434.10^{ - 3}}\)
Vậy \(\left[ {{I_2}} \right] = 0,0198 - 0,000434 = 0,0194M;\)
\(\left[ I \right] = 0,{86.10^{ - 3}}M.\)
