a,
$2C_6H_5OH+ 2Na \to 2C_6H_5ONa+ H_2$
$2C_2H_5OH+ 2Na \to 2C_6H_5ONa+ H_2$
$C_6H_5OH+3Br_2\to C_6H_2Br_3OH\downarrow+ 3HBr$
Gọi a, b là mol phenol, etanol
$n_{H_2}=0,2 mol$
$\Rightarrow 0,5a+0,5b=0,2$ (1)
$n_{Br_2}= 0,3 mol$
$\Rightarrow 3a=0,3$ (2)
(1)(2) $\Rightarrow a=0,1; b=0,3$
$\%m_{C_6H_5OH}=\frac{0,1.94.100}{0,1.94+0,3.46}= 40,5\%$
$\%m_{C_2H_5OH}= 59,5\%$
b,
$n_{C_6H_2Br_3OH\downarrow}= 0,1$
$\Rightarrow a=0,1.331=33,1g$
c,
$C_6H_5OH+KOH\to C_6H_5OK+H_2O$
$\Rightarrow n_{KOH}= 0,1 mol$
$V_{KOH}=\frac{0,1}{1,6}= 0,0625l= 62,5ml$