Có nhiều vụ tai nạn giao thông xảy ra do người lái xe uống rượu. Theo luật định, hàm lượng ethanol trong máu người lái xe không vượt quá 0,02% theo khối lượng. Để xác định hàm lượng ethanol t

$n_{K_{2}C{r}_2{O}_7}\text{=}\text{2}\text{.}\text{1}{\text{0}}^{-4}\text{m}\text{o}\text{l}$

a) $3\stackrel{-2}{C}{}_2{\text{H}}_5\text{O}\text{H}\text{+}{\text{K}}_2\stackrel{+6}{\text{C}\text{r}}{}_2{\text{O}}_7\text{+}\text{8}{H}^{+}\stackrel{}{\to }\text{3}\stackrel{-1}{\text{C}}{}_2{\text{H}}_4\text{O}\text{+}\text{2}\stackrel{+3}{Cr}\text{+}\text{2}{\text{K}}^{+}\text{+}\text{7}{\text{H}}_{2}O$

$\begin{array}{l}C{r}^{+6}\text{+}\text{3}\text{e}\stackrel{}{\to }\text{C}{\text{r}}^{+3}\\ \text{2}\text{.}\text{2}\text{.}\text{1}{\text{0}}^{-4}\to \text{1}\text{,}\text{2}\text{.}\text{1}{\text{0}}^{-3}\end{array}||\begin{array}{l}{C}_2^{-2}\stackrel{}{\to }{C}_2^{-1}\text{+}\text{2}\text{.}\text{1}\text{e}\\ \text{6}\text{.}\text{1}{\text{0}}^{-4}\stackrel{}{\leftarrow }\text{1}\text{,}\text{2}\text{.}\text{1}{\text{0}}^{-3}\end{array}$

$m_{C_2{H}_{5}OH}\text{=}\text{6}\text{.}\text{1}{\text{0}}^{-4}.46\text{=}\text{0}\text{,}\text{0}\text{2}\text{7}\text{6}\text{g}\text{a}\text{m}\stackrel{}{\to }\text{\%}{m}_{C_2{H}_{5}OH(25\text{g}\text{a}\text{m})}\text{=}\text{0}\text{,}\text{1}\text{1}\text{\%}\text{>}\text{0}\text{,}\text{0}\text{2}\text{\%}$.

Vậy người lái xe vi phạm luật giao thông.