In which one of the following , the number of protons is greater than neutrons but number of protons is less than the number of electrons

Options

A. `D_3O^+`
B. `SO_2`
C. `H_2O`
D. `OH^(-)`

Answer

To solve the question, we need to find a species where the number of protons is greater than the number of neutrons, but the number of protons is less than the number of electrons. Let's analyze each option step by step.

### Step 1: Understanding the Requirements
We need to find a species with:
1. Number of protons (Z) > Number of neutrons (N)
2. Number of protons (Z) < Number of electrons (e)

### Step 2: Analyzing Each Option
Let's analyze the given options one by one.

#### Option A: D3O+
- **Composition**: D (Deuterium) has 1 proton and 1 neutron. There are 3 Deuterium atoms and 1 Oxygen atom.
- **Protons**: 3 (from D) + 8 (from O) = 11 protons
- **Neutrons**: 3 (from D, each has 1 neutron) + 8 (from O, 16 - 8) = 11 neutrons
- **Electrons**: 11 protons - 1 (due to +1 charge) = 10 electrons
- **Comparison**: Protons = 11, Neutrons = 11, Electrons = 10
- **Conclusion**: Not valid (protons are not greater than neutrons).

#### Option B: SO2
- **Composition**: Sulfur (S) has 16 protons and 16 neutrons (32 - 16), and Oxygen (O) has 8 protons and 8 neutrons (16 - 8).
- **Protons**: 16 (from S) + 2*8 (from 2 O) = 32 protons
- **Neutrons**: 16 (from S) + 2*8 (from 2 O) = 32 neutrons
- **Electrons**: 32 (neutral species)
- **Comparison**: Protons = 32, Neutrons = 32, Electrons = 32
- **Conclusion**: Not valid (protons are not greater than neutrons).

#### Option C: H2O
- **Composition**: 2 Hydrogen (H) and 1 Oxygen (O).
- **Protons**: 2 (from H) + 8 (from O) = 10 protons
- **Neutrons**: 0 (from H) + 8 (from O) = 8 neutrons
- **Electrons**: 10 (neutral species)
- **Comparison**: Protons = 10, Neutrons = 8, Electrons = 10
- **Conclusion**: Not valid (protons are not less than electrons).

#### Option D: OH− (Hydroxide Ion)
- **Composition**: 1 Oxygen (O) and 1 Hydrogen (H).
- **Protons**: 8 (from O) + 1 (from H) = 9 protons
- **Neutrons**: 8 (from O) + 0 (from H) = 8 neutrons
- **Electrons**: 9 (from protons) + 1 (due to -1 charge) = 10 electrons
- **Comparison**: Protons = 9, Neutrons = 8, Electrons = 10
- **Conclusion**: Valid (protons > neutrons and protons < electrons).

### Final Answer
The correct option is **D: OH−**.