Give the conjugate bases of
(i) `H2_O` (ii) `HNO_3` (iii) `NH_4^+` (iv) `HCO_3^(-1)`

Explanation

To find the conjugate bases of the given acids, we need to understand that a conjugate base is formed when an acid donates a proton (H⁺). Here’s a step-by-step solution for each of the compounds listed in the question:

### Step 1: Identify the first compound, H₂O
- **Action**: Water (H₂O) can act as an acid and lose a proton (H⁺).
- **Result**: When H₂O loses H⁺, it becomes OH⁻ (hydroxide ion).
- **Conjugate Base**: OH⁻

### Step 2: Identify the second compound, HNO₃
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