X, Y (MX < MY) là hai axi...

B

- Hướng dẫn giải

Phương pháp giải:

Giải chi tiết:

\(\begin{gathered}
25,04(g)E\left\{ \begin{gathered}
X,Y \hfill \\
T \hfill \\
Z \hfill \\
\end{gathered} \right.\xrightarrow{{ + {O_2}:0,74}}\left\{ \begin{gathered}
C{O_2} \hfill \\
{H_2}O:0,8 \hfill \\
\end{gathered} \right. \hfill \\
\xrightarrow{{BTKL}}{m_{C{O_2}}} = 25,04 + 0,74.32 - 0,8.18 = 34,32(g) \to {n_{C{O_2}}} = 0,78(mol) \hfill \\
\end{gathered} \)

n_H2O>n_CO2 => Ancol no, hai chức, mạch hở 

\(\begin{gathered}
E\left\{ \begin{gathered}
{\text{Ax}}it:x \hfill \\
Ancol:y \hfill \\
Este:z \hfill \\
\end{gathered} \right. \to \left\{ \begin{gathered}
{n_{NaOH}} = x + 2z = 0,38 \hfill \\
\xrightarrow{{BTO}}2x + 2y + 4z + 0,74.2 = 0,78.2 + 0,8 \hfill \\
\xrightarrow{{n{H_2}O - nC{O_2} = {n_{ancol}} - {n_{{\text{este}}}}}}y - z = 0,8 - 0,78 \hfill \\
\end{gathered} \right. \to \left\{ \begin{gathered}
x = 0,3 \hfill \\
y = 0,06 \hfill \\
z = 0,04 \hfill \\
\end{gathered} \right. \hfill \\
\overline C = \frac{{{n_{C{O_2}}}}}{{{n_E}}} = \frac{{0,78}}{{0,3 + 0,06 + 0,04}} = 1,95 \to \left\{ \begin{gathered}
X:HCOOH \hfill \\
Y:C{H_3}COOH \hfill \\
\end{gathered} \right. \hfill \\
Quy\,doi\,E\left\{ \begin{gathered}
{C_{\overline n }}{H_{2\overline n }}{O_2}(1 < \overline n < 2):x + 2z = 0,38 \hfill \\
{C_m}{H_{2m + 2}}{O_2}(m \geqslant 3):y + z = 0,1 \hfill \\
{H_2}O: - 0,08 \hfill \\
\end{gathered} \right. \hfill \\
\xrightarrow{{BTC}}0,38\overline n + 0,1m = 0,78 \to 1 < \overline n = \frac{{0,78 - 0,1m}}{{0,38}} < 2 \to 0,2 < m < 4 \hfill \\
\to m = 3 \hfill \\
\left\{ \begin{gathered}
HCOOH:a \hfill \\
C{H_3}COOH:b \hfill \\
{C_3}{H_8}{O_2}:0,06 \hfill \\
{C_6}{H_{10}}{O_4}:0,04 \hfill \\
\end{gathered} \right. \to \left\{ \begin{gathered}
a + b = 0,3 \hfill \\
a + 2b + 3.0,06 + 6.0,04 = 0,78 \hfill \\
\end{gathered} \right. \to \left\{ \begin{gathered}
a = 0,24 \hfill \\
b = 0,06 \hfill \\
\end{gathered} \right. \hfill \\
\to \% {m_{HCOOH}} = \frac{{0,24.46}}{{25,04}}.100\% = 44,1\% \approx 45\% \hfill \\
\end{gathered} \)

Đáp án B