Orthoboric acid `(H_(3)BO_(3))` and metaboric acid `(HBO_(2))` differ in respect of :

Options

A. acidicity
B. Structure
C. Melting point
D. Oxidation

Answer

To solve the question regarding the differences between orthoboric acid `(H₃BO₃)` and metaboric acid `(HBO₂)`, we will analyze their properties step by step.

### Step 1: Analyze the Chemical Composition
- **Orthoboric Acid**: The formula is `H₃BO₃`.
- **Metaboric Acid**: The formula is `HBO₂`.

**Hint**: Look at the chemical formulas to identify the number of hydrogen and oxygen atoms in each acid.

### Step 2: Determine the Oxidation State of Boron
- For **Orthoboric Acid**:
- Let the oxidation state of boron be `X`.
- The equation is:
\[ X + 3(-1) + 3(-2) = 0 \implies X - 3 - 6 = 0 \implies X = +3 \]

- For **Metaboric Acid**:
- The equation is:
\[ X + 1(-1) + 2(-2) = 0 \implies X - 1 - 4 = 0 \implies X = +3 \]

**Hint**: Calculate the oxidation state using the known charges of hydrogen and oxygen.

### Step 3: Compare the Structures
- **Orthoboric Acid** has a **trigonal planar** structure with **sp² hybridization**.
- **Metaboric Acid** has a **linear** structure with **sp hybridization**.

**Hint**: Identify the hybridization and geometry of each compound to understand their structural differences.

### Step 4: Analyze the Melting Points
- The melting point of **metaboric acid** is higher than that of **orthoboric acid** due to its linear structure allowing for better packing of molecules.

**Hint**: Consider how molecular structure affects physical properties like melting point.

### Step 5: Compare Acidity
- **Metaboric Acid** is slightly more acidic than **Orthoboric Acid** due to the difference in structure and bonding.

**Hint**: Reflect on how structural differences can influence acidity.

### Conclusion
- **Differences**:
- Oxidation state of boron is the same in both acids.
- Different structures (trigonal planar vs. linear).
- Different melting points (metaboric acid has a higher melting point).
- Different acidity (metaboric acid is more acidic).

### Final Answer
Orthoboric acid `(H₃BO₃)` and metaboric acid `(HBO₂)` differ in terms of their structure, melting points, and acidity, but not in the oxidation state of boron.