a, (như hình)
b,
Gọi a, b là mol phenol, etanol trong m.
$n_{H_2}=\frac{1,68}{22,4}=0,075 mol$
$\Rightarrow 0,5a+0,5b=0,075$ (1)
$n_{C_6H_2Br_3OH\downarrow }= n_{C_6H_5OH}= a$
$\Rightarrow 331a=9,93$ (2)
(1)(2) $\Rightarrow a=0,03; b=0,12$
$\%m_{C_6H_5OH}=\frac{0,03.94.100}{0.03.94+0,12.46}=33,8\%$
$\%m_{C_2H_5OH}=66,2\%$