a) \(\left\{{}\begin{matrix}n_{CH_4}=\dfrac{1,68}{22,4}=0,075\left(mol\right)\\n_{Na}=\dfrac{2,3}{23}=0,1\left(mol\right)\end{matrix}\right.\)
PTHH:
\(CH_4+2O_2\xrightarrow[]{t^o}CO_2+2H_2O\)
0,075--------->0,075
\(2Na+2H_2O\rightarrow2NaOH+H_2\)
0,1---------------->0,1
b) \(m_{NaOH}=0,1.40=4\left(g\right)\)
c) Xét \(T=\dfrac{n_{NaOH}}{n_{CO_2}}=\dfrac{0,1}{0,075}=\dfrac{4}{3}\)
\(1< \dfrac{4}{3}< 2\Rightarrow\) Pư tạo 2 muối
Đặt \(\left\{{}\begin{matrix}n_{Na_2CO_3}=a\left(mol\right)\\n_{NaHCO_3}=b\left(mol\right)\end{matrix}\right.\)
PTHH:
\(2NaOH+CO_2\rightarrow Na_2CO_3+H_2O\)
2a<---------a<-------a
\(NaOH+CO_2\rightarrow NaHCO_3\)
b<----------b<-------b
\(\Rightarrow\left\{{}\begin{matrix}2a+b=0,1\\a+b=0,075\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,025\\b=0,05\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}C_{M\left(Na_2CO_3\right)}=\dfrac{0,025}{0,25}=0,1M\\C_{M\left(NaHCO_3\right)}=\dfrac{0,05}{0,25}=0,2M\end{matrix}\right.\)