`2.8` g of KOH is dissolved in water to give 200 `cm^(3)` of Solution Calculate the molarity of KOH in the Solution .

Answer

To find the molarity of KOH in the solution, we will follow these steps:

### Step 1: Calculate the Molar Mass of KOH
- Potassium (K) has an atomic mass of approximately 39 g/mol.
- Oxygen (O) has an atomic mass of approximately 16 g/mol.
- Hydrogen (H) has an atomic mass of approximately 1 g/mol.

**Molar Mass of KOH** = Atomic mass of K + Atomic mass of O + Atomic mass of H
= 39 g/mol + 16 g/mol + 1 g/mol
= 56 g/mol

### Step 2: Calculate the Number of Moles of KOH
To find the number of moles of KOH, we use the formula:

\[ \text{Number of moles} = \frac{\text{mass of solute (g)}}{\text{molar mass (g/mol)}} \]

Given:
- Mass of KOH = 2.8 g
- Molar mass of KOH = 56 g/mol

\[ \text{Number of moles of KOH} = \frac{2.8 \text{ g}}{56 \text{ g/mol}} = 0.05 \text{ moles} \]

### Step 3: Convert the Volume of the Solution to Liters
The volume of the solution is given as 200 cm³. We need to convert this to liters:

\[ \text{Volume in liters} = \frac{200 \text{ cm}^3}{1000} = 0.2 \text{ L} \]

### Step 4: Calculate the Molarity of KOH
Molarity (M) is defined as the number of moles of solute per liter of solution:

\[ \text{Molarity (M)} = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}} \]

Using the values we calculated:

\[ \text{Molarity (M)} = \frac{0.05 \text{ moles}}{0.2 \text{ L}} = 0.25 \text{ M} \]

### Final Answer
The molarity of KOH in the solution is **0.25 M**.

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