`B(OH)_(3)` will accept how many `OH^(-)` ions?

Options

A. 1
B. 2
C. 3
D. 4

Answer

To determine how many hydroxide ions (`OH^(-)`) the compound boron trihydroxide (`B(OH)₃`) can accept, we can follow these steps:

### Step 1: Understand the Structure of `B(OH)₃`
Boron trihydroxide consists of a boron atom bonded to three hydroxide ions. The structure is trigonal planar due to the sp² hybridization of the boron atom.

### Step 2: Analyze the Electron Configuration of Boron
Boron has the electronic configuration of `1s² 2s² 2p¹`. In its ground state, boron has three valence electrons. When forming compounds, it can promote one of its `2s` electrons to the `2p` level, resulting in an excited state configuration of `1s² 2s¹ 2p²`.

### Step 3: Determine Boron's Electron Deficiency
Boron is electron deficient because it has only six electrons in its valence shell (three from the three `OH` groups). This means that boron does not have a complete octet (which requires eight electrons).

### Step 4: Identify Boron's Role as a Lewis Acid
Due to its electron deficiency, boron can act as a Lewis acid, which means it can accept electron pairs from other species. In this case, it can accept hydroxide ions.

### Step 5: Calculate the Maximum Covalency of Boron
Boron can form a maximum of four covalent bonds because it has one `s` and three `p` orbitals available for bonding. Currently, it has already formed three bonds with the three hydroxide ions.

### Step 6: Determine How Many Additional Hydroxide Ions Can Be Accepted
Since boron has already formed three bonds, it can accept only one more hydroxide ion to complete its octet. This means that `B(OH)₃` can accept one additional `OH^(-)` ion.

### Conclusion
Therefore, the answer to the question is that `B(OH)₃` will accept **one hydroxide ion**.

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