V lớn nhất khi dung dịch X chỉ chứa muối \(HCO_3^-\)
Vì \(CM_{KOH}=2CM_{NaOH}\) \(\Rightarrow n_{K_2CO_3}=2n_{Na_2CO_3}\)
Hỗn hợp muối gồm: \(\left\{{}\begin{matrix}Na_2CO_3:a\left(mol\right)\\K_2CO_3:2a\left(mol\right)\end{matrix}\right.\)
\(m_{muối}=106a+138.2a=19,1\) \(\Rightarrow a=0,05\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{NaHCO_3}=0,05\left(mol\right)\\n_{KHCO_3}=0,1\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow n_{CO_2}=0,15\left(mol\right)\Rightarrow V=0,15.22,4=3,36\left(l\right)\)