6.8 g `H_(2)O_(2)` present in 100 mL of its solution. What is the molarity of solution?

Options

A. 1 M
B. 2 M
C. 3 M
D. 0.5 M

Explanation

To find the molarity of the solution containing 6.8 g of H₂O₂ in 100 mL of solution, we can follow these steps:

### Step 1: Calculate the Molar Mass of H₂O₂
The molar mass of H₂O₂ (Hydrogen Peroxide) can be calculated as follows:
- Hydrogen (H) has a molar mass of approximately 1 g/mol.
- Oxygen (O) has a molar mass of approximately 16 g/mol.

The chemical formula for hydrogen peroxide is H₂O₂, which means it contains:
- 2 Hydrogen atoms: 2 × 1 g/mol = 2 g/mol
- 2 Oxygen atoms: 2 × 16 g/mol = 32 g/mol

Adding these together:
\[ \text{Molar mass of H₂O₂} = 2 + 32 = 34 \text{ g/mol} \]

### Step 2: Calculate the Number of Moles of H₂O₂
To find the number of moles of H₂O₂ in the solution, we use the formula:
\[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \]

Substituting the values:
\[ \text{Number of moles} = \frac{6.8 \text{ g}}{34 \text{ g/mol}} = 0.2 \text{ moles} \]

### Step 3: Convert the Volume of the Solution to Liters
Since molarity is defined as moles of solute per liter of solution, we need to convert the volume from milliliters to liters:
\[ 100 \text{ mL} = \frac{100}{1000} \text{ L} = 0.1 \text{ L} \]

### Step 4: Calculate the Molarity of the Solution
Now we can calculate the molarity (M) using the formula:
\[ \text{Molarity (M)} = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}} \]

Substituting the values:
\[ \text{Molarity (M)} = \frac{0.2 \text{ moles}}{0.1 \text{ L}} = 2 \text{ M} \]

### Final Answer
The molarity of the H₂O₂ solution is **2 M**.

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