Write the conjugate acid/base for the following species:
`HNO_2 , CN^(-) , HClO_4 , F^(-) , OH^(-) ,CO_3^(2-)` and `S^(2-)`

Answer

To find the conjugate acids and bases for the given species, we need to understand the definitions of conjugate acids and bases:

- A **conjugate acid** is formed when a base accepts a proton (H⁺).
- A **conjugate base** is formed when an acid donates a proton (H⁺).

Now, let's analyze each species step by step:

### Step 1: HNO₂
- **Type**: Acid (can donate H⁺)
- **Conjugate Base**: HNO₂ - H⁺ → NO₂⁻
- **Result**: Conjugate base is NO₂⁻.

### Step 2: CN⁻
- **Type**: Base (can accept H⁺)
- **Conjugate Acid**: CN⁻ + H⁺ → HCN
- **Result**: Conjugate acid is HCN.

### Step 3: HClO₄
- **Type**: Acid (can donate H⁺)
- **Conjugate Base**: HClO₄ - H⁺ → ClO₄⁻
- **Result**: Conjugate base is ClO₄⁻.

### Step 4: F⁻
- **Type**: Base (can accept H⁺)
- **Conjugate Acid**: F⁻ + H⁺ → HF
- **Result**: Conjugate acid is HF.

### Step 5: OH⁻
- **Type**: Base (can accept H⁺)
- **Conjugate Acid**: OH⁻ + H⁺ → H₂O
- **Result**: Conjugate acid is H₂O.

### Step 6: CO₃²⁻
- **Type**: Base (can accept H⁺)
- **Conjugate Acid**: CO₃²⁻ + H⁺ → HCO₃⁻
- **Result**: Conjugate acid is HCO₃⁻.

### Step 7: S²⁻
- **Type**: Base (can accept H⁺)
- **Conjugate Acid**: S²⁻ + H⁺ → HS⁻
- **Result**: Conjugate acid is HS⁻.

### Summary of Results:
- HNO₂ → Conjugate Base: NO₂⁻
- CN⁻ → Conjugate Acid: HCN
- HClO₄ → Conjugate Base: ClO₄⁻
- F⁻ → Conjugate Acid: HF
- OH⁻ → Conjugate Acid: H₂O
- CO₃²⁻ → Conjugate Acid: HCO₃⁻
- S²⁻ → Conjugate Acid: HS⁻