Which of the following has five donor (coordinating) sites?
(a) Ethylenediaminetriacetate ion
(b) Diethylene triamine
(c ) Ethylenediaminetetracetate ion
(d) Triethylene tetramine .

Explanation

To determine which of the given compounds has five donor (coordinating) sites, we will analyze each option one by one.

### Step 1: Analyze Ethylenediaminetriacetate ion (EDTA³⁻)
- **Structure**: The ethylenediaminetriacetate ion consists of an ethylene backbone (–CH₂–CH₂–) with two nitrogen atoms (N) and three acetate groups (–COO⁻).
- **Donor Sites**:
- Each acetate group contributes one oxygen atom (O) with a negative charge as a donor site.
- The two nitrogen atoms each have a lone pair that can act as donor sites.
- **Total Donor Sites**:
- 3 (from acetate) + 2 (from nitrogen) = 5 donor sites.

### Step 2: Analyze Diethylene triamine
- **Structure**: Diethylene triamine has two ethylene groups and three nitrogen atoms.
- **Donor Sites**:
- Each nitrogen atom has a lone pair that can act as a donor site.
- **Total Donor Sites**:
- 3 (from nitrogen) = 3 donor sites.

### Step 3: Analyze Ethylenediaminetetraacetate ion (EDTA⁴⁻)
- **Structure**: The ethylenediaminetetraacetate ion consists of an ethylene backbone with two nitrogen atoms and four acetate groups.
- **Donor Sites**:
- Each acetate group contributes one oxygen atom (O) with a negative charge as a donor site.
- The two nitrogen atoms each have a lone pair that can act as donor sites.
- **Total Donor Sites**:
- 4 (from acetate) + 2 (from nitrogen) = 6 donor sites.

### Step 4: Analyze Triethylene tetramine
- **Structure**: Triethylene tetramine has three ethylene groups and four nitrogen atoms.
- **Donor Sites**:
- Each nitrogen atom has a lone pair that can act as a donor site.
- **Total Donor Sites**:
- 4 (from nitrogen) = 4 donor sites.

### Conclusion
After analyzing all the options:
- **Ethylenediaminetriacetate ion (EDTA³⁻)** has 5 donor sites.
- **Diethylene triamine** has 3 donor sites.
- **Ethylenediaminetetraacetate ion (EDTA⁴⁻)** has 6 donor sites.
- **Triethylene tetramine** has 4 donor sites.

Thus, the correct answer is **(a) Ethylenediaminetriacetate ion**.