Xà phòng hóa hoàn toàn m gam

Chọn đáp án D

Giải thích:

$\begin{array}{l}+E\text{'}la\left\{\begin{array}{l}O:72a\\ C:660a\\ H:b\end{array}\right\}\stackrel{quydoi}{\leftarrow }Elaø\left\{\begin{array}{l}{C}_3{H}_5{\left(OOC{C}_{17}{H}_x\right)}_3:3amol\\ C_3{H}_5{\left(OOC{C}_{15}{H}_{31}\right)}_3:4amol\\ C_3{H}_5{\left(OOC{C}_{17}{H}_y\right)}_3:5amol\end{array}\right\}\stackrel{H_2(Ni,t^o)}{\to }\underset{Y}{\underbrace{\left\{\begin{array}{l}{C}_3{H}_5{\left(OOC{C}_{17}{H}_{35}\right)}_3:8a\\ C_3{H}_5{\left(OOC{C}_{15}{H}_{31}\right)}_3:4a\end{array}\right\}}}\\ +m_Y=890.8a+806.4a=\mathrm{68,96}\Rightarrow a=\frac{1}{150}\\ +BTNT\left(O\right):72a+\mathrm{6,14.2}=\mathrm{2.660.}a+\frac{b}{2}\Rightarrow b=\mathrm{7,92}\Rightarrow m_E=m_{E^{\text{'}}}=\mathrm{68,4}gam.\end{array}$