\(a.n_{CO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\\ CO_2+Ba\left(OH\right)_2\rightarrow BaCO_3+H_2O\\ 0,1...........0,1.............0,1..........0,1\left(mol\right)\\ b.m_{kt}=m_{BaCO_3}=0,1.197=19,7\left(g\right)\\ c.C_{MddBa\left(OH\right)_2}=\dfrac{0,1}{0,2}=0,5\left(M\right)\)