Xà phòng hóa hoàn toàn m gam chất béo trung tính b...

B

- Hướng dẫn giải

Phương pháp giải:

Giả sử chất béo là \({(\overline R C{\text{OO)}}_{\text{3}}}{{\text{C}}_{\text{3}}}{{\text{H}}_{\text{5}}}\)

\(\begin{gathered}
{(\overline R C{\text{OO)}}_{\text{3}}}{{\text{C}}_{\text{3}}}{{\text{H}}_{\text{5}}}\xrightarrow{{ + KOH}}3\overline R C{\text{OO}}K \hfill \\
{(\overline R C{\text{OO)}}_{\text{3}}}{{\text{C}}_{\text{3}}}{{\text{H}}_{\text{5}}}\xrightarrow{{ + NaOH}}3\overline R C{\text{OONa}} \hfill \\
\,\,\,\,\,\,\,\,\overline R C{\text{OO}}K..............\overline R C{\text{OONa}} \hfill \\
PT:\overline R + 83..................\overline R + 67 \hfill \\
DB:18,77g................17,81g \hfill \\
\to 18,77(\overline R + 67) = 17,81(\overline R + 83) \hfill \\
\to \overline R \hfill \\
\end{gathered} \)