Total number of molecules which can form H-bond among themselves.
`SiH_(3)OH, HCN, B(OM e)_(3), NHM e_(2), CH_(3)CONH_(2), HCHO, HCOOH, NH_(2)OH, H_(4)SiO_(4)`

Explanation

To determine the total number of molecules that can form hydrogen bonds among the given compounds, we will analyze each molecule based on the presence of hydrogen atoms bonded to highly electronegative atoms (like oxygen, nitrogen, or fluorine).

### Step-by-Step Solution:

1. **Identify the Molecules**: The given molecules are:
- SiH₃OH
- HCN
- B(OMe)₃
- NHMe₂
- CH₃CONH₂
- HCHO
- HCOOH
- NH₂OH
- H₄SiO₄

2. **Analyze Each Molecule for Hydrogen Bonding**:
- **SiH₃OH**: This molecule has an -OH group, which can participate in hydrogen bonding. **(Forms H-bond)**
- **HCN**: The hydrogen is bonded to carbon, not to a highly electronegative atom like oxygen or nitrogen. **(Does not form H-bond)**
- **B(OMe)₃**: The hydrogens in this molecule are attached to carbon (in the -OMe groups), and there is no hydrogen directly bonded to oxygen or nitrogen. **(Does not form H-bond)**
- **NHMe₂**: This molecule has a nitrogen atom with a hydrogen atom attached, allowing for hydrogen bonding. **(Forms H-bond)**
- **CH₃CONH₂**: The presence of the -NH₂ group allows this molecule to form hydrogen bonds. **(Forms H-bond)**
- **HCHO**: The hydrogen is bonded to carbon, so it does not participate in hydrogen bonding. **(Does not form H-bond)**
- **HCOOH**: This is a carboxylic acid with an -OH group, which can form hydrogen bonds. **(Forms H-bond)**
- **NH₂OH**: This molecule has both nitrogen and oxygen, allowing it to form hydrogen bonds. **(Forms H-bond)**
- **H₄SiO₄**: This molecule has multiple -OH groups, which can participate in hydrogen bonding. **(Forms H-bond)**

3. **Count the Molecules that Can Form Hydrogen Bonds**:
- The molecules that can form hydrogen bonds are:
- SiH₃OH
- NHMe₂
- CH₃CONH₂
- HCOOH
- NH₂OH
- H₄SiO₄
- Total = 6 molecules

### Final Answer:
The total number of molecules that can form hydrogen bonds among themselves is **6**.