\(n_{SO_2}=\dfrac{11,2}{22,4}=0,5mol\\ n_{Ca\left(OH\right)_2}=0,2.0,5=0,1mol\\ SO_2+Ca\left(OH\right)_2\rightarrow CaSO_3+H_2O\\ \Rightarrow\dfrac{0,5}{1}>\dfrac{0,1}{1}\Rightarrow SO_2.dư\\ n_{SO_2.pứ}=n_{Ca\left(OH\right)_2}=0,1mol\\ m_{SO_2.dư}=\left(0,5-0,1\right).64=25,6g\)