Incorrect order between following compounds is/are:

Options

A. `O(CH_(3))_(2)ltO(SiH_(3))_(2)` : number of `sp^(3)`-hybride atoms
B. `O(CH_(3))_(2)ltO(SiH_(3))_(2)` : Bond angle w.r.t common atom
C. `O(CH_(3))_(2)ltO(SiH_(3))_(2)` :% s-character of hybrid orbital on central atom
D. `O(CH_(3))_(2)ltO(SiH_(3))_(2)` : reactivity towards lewis acid

Answer

To determine the incorrect order between the given compounds, we will analyze the statements provided in the question step by step.

### Step 1: Identify the Compounds
We have two compounds to analyze, which include OCH3 (methoxy) and OSiH3 (silyl ether). We need to compare their properties, specifically focusing on hybridization, bond angles, percentage s-character, and reactivity towards Lewis acids.

### Step 2: Determine Hybridization
- **OCH3**: The central atom is carbon (C) which is sp3 hybridized. It has 4 sigma bonds (3 from H and 1 from O).
- **OSiH3**: The central atom is silicon (Si) which is also sp3 hybridized. It has 4 sigma bonds (3 from H and 1 from O).

Both compounds have the same hybridization (sp3).

### Step 3: Analyze Bond Angles
- In OCH3, the bond angle is approximately 109.5° due to the tetrahedral geometry of sp3 hybridization.
- In OSIH3, silicon has a larger atomic size and has vacant d-orbitals that can participate in back-bonding. This back-bonding can increase the bond angle compared to OCH3.

Thus, OSIH3 has a greater bond angle than OCH3.

### Step 4: Percentage s-Character
- For both OCH3 and OSiH3, since they are sp3 hybridized, the percentage s-character is 25% (1 out of 4 orbitals is s).

Thus, the percentage s-character is equal for both compounds.

### Step 5: Reactivity Towards Lewis Acids
- OCH3 can act as a Lewis base because it has available electrons to donate.
- OSiH3, due to back-bonding, has its electrons involved in bonding, making it less available to donate, thus making it a poorer Lewis base compared to OCH3.

### Conclusion
Based on the analysis:
- **Incorrect Statements**:
- A: Number of sp3 hybridized atoms is equal in both compounds (True).
- B: Bond angle in OSiH3 is greater than in OCH3 (True).
- C: Percentage s-character is equal in both compounds (True).
- D: Reactivity towards Lewis acids (OSiH3 is a better Lewis acid) (True).

Thus, the incorrect statements are A, C, and D.