\(SO_3+H_2O\rightarrow H_2SO_4\\ n_{H_2SO_4}=n_{SO_3}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\\ a,m=m_{H_2SO_4}=98.0,3=29,4\left(g\right)\\ b,C\%_{ddH_2SO_4}=\dfrac{29,4}{0,3.80+150}.100\approx16,897\%\\ c,H_2SO_4:Tính.axit\Rightarrow Quỳ.tím.hoá.đỏ\)