One gm equivalent of substance present in :-

Options

A. `0.25 "mole" O_(2)`
B. `0.5 "mole" of O_(2)`
C. `1.00 "mole" of O_(2)`
D. `8.00 "mole" of O_(20)`

Explanation

To solve the problem of determining which option contains 1 gram equivalent of a substance (specifically oxygen), we will follow these steps:

### Step 1: Understand the concept of gram equivalent
1 gram equivalent of a substance is defined as the amount of that substance that will combine with or displace 1 mole of hydrogen or 8 grams of oxygen. For oxygen (O2), the molar mass is 32 grams (16 grams per atom, and there are two atoms in O2).

### Step 2: Calculate the mass of 1 gram equivalent of oxygen
Since 1 gram equivalent of oxygen is 8 grams, we need to find out which option corresponds to this mass.

### Step 3: Analyze the options
We will calculate the mass of oxygen in each option based on the molarity provided.

1. **Option A: 0.25 Molar of O2**
- Molar mass of O2 = 32 g/mol
- Mass = Molarity × Volume (assuming 1 liter for simplicity)
- Mass = 0.25 mol/L × 32 g/mol = 8 grams

2. **Option B: 0.5 Molar of O2**
- Mass = 0.5 mol/L × 32 g/mol = 16 grams

3. **Option C: 1 Molar of O2**
- Mass = 1 mol/L × 32 g/mol = 32 grams

4. **Option D: 0.25 Molar of O2 (again)**
- Mass = 0.25 mol/L × 32 g/mol = 8 grams

### Step 4: Identify the correct option
From our calculations:
- Option A has 8 grams of O2, which corresponds to 1 gram equivalent.
- Option B has 16 grams.
- Option C has 32 grams.
- Option D also has 8 grams.

Thus, the options that contain 1 gram equivalent of oxygen are **Option A** and **Option D**.

### Final Answer:
**Option A** (0.25 Molar of O2) contains 1 gram equivalent of oxygen.