\(m_{C_6H_{12}O_6}=2.5\cdot80\%=2\left(kg\right)\)
\(n_{C_6H_{12}O_6}=\dfrac{2}{180}=\dfrac{1}{90}\left(kmol\right)\)
\(\Rightarrow n_{C_2H_5OH}=2\cdot\dfrac{1}{90}=\dfrac{1}{45}\left(kmol\right)\)
\(m_{C_2H_5OH\left(tt\right)}=\dfrac{1}{45}\cdot46\cdot90\%=0.92\left(kg\right)\)