The following figure shows a polymer with a multi-chain structure, which can be prepared as follows: Dissolve ${ \mathbf A } ( \mathrm{C_6H_8O_3Si} )$ in dioxane, and gradually add a dioxane solution of $\mathbf B (\mathrm{C_2H_6O_2Cl_2Si) }$ and triethylamine under argon protection to prepare monomer $\bf{C}$; $\bf{C}$ undergoes dehydration under triethylamine catalysis to obtain polymer $\bf{D}$; Dissolve $\bf{D}$ in $\rm{THF}$, add a small amount of dilute hydrochloric acid, and stir thoroughly at room temperature for sufficient reaction; The resulting product undergoes dehydration again under triethylamine catalysis to obtain $\bf{E}$; Finally, add a toluene solution of $\bf{F}$ to $\bf{E}$ for end-capping to obtain the final product.

<MultiModal>![This is a polymer. The repeating unit is [R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si]([R1])(O3)O[Si]([R1])(C4=CC=CC=C4)O[Si](O[R2])(C5=CC=CC=C5)O[Si]3(O[R2])O1)C6=CC=CC=C6, R1 and R2 are the connection sites of the repeating unit; the terminal group R1 connected to $\rm{Si}$ is $\rm{-OSiMe_3}$, and the terminal group R2 connected to $\rm{O}$ is $\rm{-SiMe_3}$](/media/uploads/a07149e4-a5b8-4ac2-a1ca-31095036e6f0.png)</MultiModal>

Which of the following statements is incorrect?
下图是一种具有多链结构的聚合物，其可按照如下方法制备：将 ${ \mathbf A } ( \mathrm{C_6H_8O_3Si} )$ 溶于二氧六环中，在氩气保护下逐渐滴加$\mathbf B (\mathrm{C_2H_6O_2Cl_2Si) }$ 和三乙胺的二氧六环溶液，制得单体$\bf{C}$；$\bf{C}$在三乙胺催化下发生脱水，得到聚合物$\bf{D}$；将$\bf{D}$溶于$\rm{THF}$，加入少量稀盐酸，室温搅拌充分反应；得到的产物在三乙胺催化下再次发生脱水，得到$\bf{E}$；最后，向$\bf{E}$中加入$\bf{F}$的甲苯溶液反应封端，制得最终产物。

<MultiModal>![这是一个高分子聚合物。重复单元为[R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si]([R1])(O3)O[Si]([R1])(C4=CC=CC=C4)O[Si](O[R2])(C5=CC=CC=C5)O[Si]3(O[R2])O1)C6=CC=CC=C6，R1和R2是重复单元的连接位点；与$\rm{Si}$相连的端基R1为$\rm{-OSiMe_3}$，与$\rm{O}$相连的端基R2为$\rm{-SiMe_3}$](/media/uploads/a07149e4-a5b8-4ac2-a1ca-31095036e6f0.png)</MultiModal>

下列说法中错误的是
$\bf{A}$ contains three hydroxyl groups.
$\bf{B}$ contains 2 methoxy groups.
$\bf{C}$ contains 8 $\rm{C}$
$\bf{D}$ contains a 12-membered ring
The repeating unit in $\bf{E}$ contains 7 $\rm{O}$.
$\bf{A}$中包含三个羟基
$\bf{B}$中包含2个甲氧基
$\bf{C}$中包含8个$\rm{C}$
$\bf{D}$中包含12元环
$\bf{E}$中重复单元包含7个$\rm{O}$
Based on the product structure, $\bf{A}$ and $\bf{B}$ should be two small units of the polymer structure. Since $\bf{A}$ contains 6 $\rm{C}$ atoms, it can be determined that $\bf{A}$ is the part connected to the benzene ring, namely $\rm{Si(OH)_3(C_6H_5)}$, O[Si](O)(O)C1=CC=CC=C1. $\bf{A}$ contains three hydroxyl groups, so A is correct.

<Checkpoint>[$\bf{A}$ is O[Si](O)(O)C1=CC=CC=C1](1.5)</Checkpoint>

$\bf{B}$ should be a structure not connected to the benzene ring. Combined with the molecular formula, it can be determined as $\rm{Si(OCH_3)_2Cl_2}$, namely Cl[Si](Cl)(OC)OC. $\bf{B}$ contains 2 methoxy groups, so B is correct.

<Checkpoint>[$\bf{B}$ is Cl[Si](Cl)(OC)OC](1.5)</Checkpoint>

The question indicates that $\bf{C}$ is a monomer obtained from the reaction of $\bf{A}$ and $\bf{B}$, which is only the substitution of $\rm{O}$ for $\rm{Cl}$, i.e., $\bf{C}$ is O[Si](O[Si](OC)(OC)O[Si](O)(C1=CC=CC=C1)O)(O)C2=CC=CC=C2. $\bf{C}$ contains 12 $\rm{C}$ atoms, so C is incorrect.

<Checkpoint>[$\bf{C}$ is O[Si](O[Si](OC)(OC)O[Si](O)(C1=CC=CC=C1)O)(O)C2=CC=CC=C2](1)</Checkpoint>

From "$\bf{C}$ undergoes dehydration under triethylamine catalysis to obtain polymer $\bf{D}$", it can be determined that hydroxyl groups are connected in this step, which is the polymerization process, i.e., the repeating unit of $\bf{D}$ is [R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si](OC)(OC)O[Si]([R1])(C3=CC=CC=C3)O[Si](O[R2])(C4=CC=CC=C4)O[Si](OC)(OC)O1)C5=CC=CC=C5, R1 and R2 are the connection sites of the repeating unit; the terminal group R1 near $\rm{Si}$ is 2 $\rm{OH}$, and the terminal group R2 near $\rm{O}$ is 2 $\rm{H}$. $\bf{D}$ contains a 12-membered ring, so D is correct.

<Checkpoint>[$\bf{D}$'s repeating unit is [R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si](OC)(OC)O[Si]([R1])(C3=CC=CC=C3)O[Si](O[R2])(C4=CC=CC=C4)O[Si](OC)(OC)O1)C5=CC=CC=C5, R1 and R2 are the connection sites of the repeating unit; the terminal group R1 near $\rm{Si}$ is 2 $\rm{OH}$, and the terminal group R2 near $\rm{O}$ is 2 $\rm{H}$](1)</Checkpoint>

Subsequently, the addition of hydrochloric acid will hydrolyze the methoxy groups into hydroxyl groups, and then the hydroxyl groups formed by hydrolysis undergo dehydration polymerization. Therefore, the repeating unit of $\bf{E}$ is [R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si]([R1])(O3)O[Si]([R1])(C4=CC=CC=C4)O[Si](O[R2])(C5=CC=CC=C5)O[Si]3(O[R2])O1)C6=CC=CC=C6, R1 and R2 are the connection sites of the repeating unit; the terminal group R1 near $\rm{Si}$ is 3 $\rm{OH}$, and the terminal group R2 near $\rm{O}$ is 3 $\rm{H}$. The repeating unit with the smallest number of molecules in $\bf{E}$ contains 7 $\rm{O}$ atoms, so E is correct.

<Checkpoint>[$\bf{E}$'s repeating unit is [R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si]([R1])(O3)O[Si]([R1])(C4=CC=CC=C4)O[Si](O[R2])(C5=CC=CC=C5)O[Si]3(O[R2])O1)C6=CC=CC=C6, R1 and R2 are the connection sites of the repeating unit; the terminal group R1 near $\rm{Si}$ is 3 $\rm{OH}$, and the terminal group R2 near $\rm{O}$ is 3 $\rm{H}$](1)</Checkpoint>

$\bf{F}$ is a capping agent and, based on the product structure, should be $\rm{SiMe_3X}$, $\rm{X=Cl、Br、OTf}$. Since it is not fixed, no further questions are asked.

In summary, choose option C.

<MultiModal>![Structures of $\bf{A}$ to $\bf{E}$. $\bf{A}$ is O[Si](O)(O)C1=CC=CC=C1; $\bf{B}$ is Cl[Si](Cl)(OC)OC; $\bf{C}$ is O[Si](O[Si](OC)(OC)O[Si](O)(C1=CC=CC=C1)O)(O)C2=CC=CC=C2; The repeating unit of $\bf{D}$ is [R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si](OC)(OC)O[Si]([R1])(C3=CC=CC=C3)O[Si](O[R2])(C4=CC=CC=C4)O[Si](OC)(OC)O1)C5=CC=CC=C5, R1 and R2 are the connection sites of the repeating unit; the terminal group R1 near $\rm{Si}$ is 2 $\rm{OH}$, and the terminal group R2 near $\rm{O}$ is 2 $\rm{H}$; The repeating unit of $\bf{E}$ is [R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si]([R1])(O3)O[Si]([R1])(C4=CC=CC=C4)O[Si](O[R2])(C5=CC=CC=C5)O[Si]3(O[R2])O1)C6=CC=CC=C6, R1 and R2 are the connection sites of the repeating unit; the terminal group R1 near $\rm{Si}$ is 3 $\rm{OH}$, and the terminal group R2 near $\rm{O}$ is 3 $\rm{H}$](/media/uploads/48b1d302-d86d-4966-bc5b-15f698af94c0.png)</MultiModal>
根据产物结构进行反推，$\bf{A}$和$\bf{B}$应当为聚合物结构的两个小单元。由于$\bf{A}$中含6个$\rm{C}$，可以判断$\bf{A}$为和苯环相连的部分，即$\rm{Si(OH)_3(C_6H_5)}$，O[Si](O)(O)C1=CC=CC=C1。$\bf{A}$中包含三个羟基，A正确。

<Checkpoint>[$\bf{A}$为O[Si](O)(O)C1=CC=CC=C1](1.5)</Checkpoint>

$\bf{B}$应为不和苯环相连的结构，结合分子式可以判断为$\rm{Si(OCH_3)_2Cl_2}$，即Cl[Si](Cl)(OC)OC。$\bf{B}$中包含2个甲氧基，B正确。

<Checkpoint>[$\bf{B}$为Cl[Si](Cl)(OC)OC](1.5)</Checkpoint>

题干表明，$\bf{C}$为$\bf{A}$和$\bf{B}$反应得到的单体，则仅为$\rm{O}$对$\rm{Cl}$的取代，即$\bf{C}$为O[Si](O[Si](OC)(OC)O[Si](O)(C1=CC=CC=C1)O)(O)C2=CC=CC=C2。$\bf{C}$中包含12个$\rm{C}$，C错误。

<Checkpoint>[$\bf{C}$为O[Si](O[Si](OC)(OC)O[Si](O)(C1=CC=CC=C1)O)(O)C2=CC=CC=C2](1)</Checkpoint>

由”$\bf{C}$在三乙胺催化下发生脱水，得到聚合物$\bf{D}$“，可以判断这一步骤发生了羟基相连，聚合的过程，即$\bf{D}$的重复单元为[R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si](OC)(OC)O[Si]([R1])(C3=CC=CC=C3)O[Si](O[R2])(C4=CC=CC=C4)O[Si](OC)(OC)O1)C5=CC=CC=C5，R1和R2是重复单元的连接位点；靠近$\rm{Si}$的端基R1为2个$\rm{OH}$，靠近$\rm{O}$的端基R2为2个$\rm{H}$。$\bf{D}$中包含12元环，D正确。

<Checkpoint>[$\bf{D}$的重复单元为[R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si](OC)(OC)O[Si]([R1])(C3=CC=CC=C3)O[Si](O[R2])(C4=CC=CC=C4)O[Si](OC)(OC)O1)C5=CC=CC=C5，R1和R2是重复单元的连接位点；靠近$\rm{Si}$的端基R1为2个$\rm{OH}$，靠近$\rm{O}$的端基R2为2个$\rm{H}$](1)</Checkpoint>

随后，加入盐酸，会将甲氧基水解成羟基，然后水解形成的羟基发生脱水聚合。因此$\bf{E}$的重复单元为[R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si]([R1])(O3)O[Si]([R1])(C4=CC=CC=C4)O[Si](O[R2])(C5=CC=CC=C5)O[Si]3(O[R2])O1)C6=CC=CC=C6，R1和R2是重复单元的连接位点；靠近$\rm{Si}$的端基R1为3个$\rm{OH}$，靠近$\rm{O}$的端基R2为3个$\rm{H}$。$\bf{E}$中分子数最小的重复单元包含7个$\rm{O}$，E正确。

<Checkpoint>[$\bf{E}$的重复单元为[R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si]([R1])(O3)O[Si]([R1])(C4=CC=CC=C4)O[Si](O[R2])(C5=CC=CC=C5)O[Si]3(O[R2])O1)C6=CC=CC=C6，R1和R2是重复单元的连接位点；靠近$\rm{Si}$的端基R1为3个$\rm{OH}$，靠近$\rm{O}$的端基R2为3个$\rm{H}$](1)</Checkpoint>

$\bf{F}$为封端试剂，根据产物结构，应当为$\rm{SiMe_3X}$，$\rm{X=Cl、Br、OTf}$。由于不固定，不再设问。

综上，选择C选项。

<MultiModal>![$\bf{A}~\bf{E}$结构。$\bf{A}$为O[Si](O)(O)C1=CC=CC=C1；$\bf{B}$为Cl[Si](Cl)(OC)OC；$\bf{C}$为O[Si](O[Si](OC)(OC)O[Si](O)(C1=CC=CC=C1)O)(O)C2=CC=CC=C2；$\bf{D}$的重复单元为[R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si](OC)(OC)O[Si]([R1])(C3=CC=CC=C3)O[Si](O[R2])(C4=CC=CC=C4)O[Si](OC)(OC)O1)C5=CC=CC=C5，R1和R2是重复单元的连接位点；靠近$\rm{Si}$的端基R1为2个$\rm{OH}$，靠近$\rm{O}$的端基R2为2个$\rm{H}$；$\bf{E}$的重复单元为[R1][Si](O[Si]1(O[R2])C2=CC=CC=C2)(O[Si]([R1])(O3)O[Si]([R1])(C4=CC=CC=C4)O[Si](O[R2])(C5=CC=CC=C5)O[Si]3(O[R2])O1)C6=CC=CC=C6，R1和R2是重复单元的连接位点；靠近$\rm{Si}$的端基R1为3个$\rm{OH}$，靠近$\rm{O}$的端基R2为3个$\rm{H}$](/media/uploads/48b1d302-d86d-4966-bc5b-15f698af94c0.png)</MultiModal>