$n_{CO_2}=4,48/22,4=0,2mol$
$C_2H_5OH+3O_2\overset{t^o}\to 2CO_2+3H_2O$
a.Theo pt :
$n_{C_2H_5OH}=1/2.n_{CO_2}=1/2.0,2=0,1mol$
$⇒m_{C_2H_5OH}=0,1.36=3,6g$
b.Theo pt :
$n_{O_2}=3.n_{C_2H_5OH}=3.0,2=0,6mol$
$⇒V_{Kkk}=0,6.22,4.5=67,2l$
$c.V_{rượu}=\dfrac{4,6}{0,8}=5,75ml$
$⇒V_{dd}=\dfrac{5,75.100}{40}=14,375ml$