8g NaOH is dissolved in one litre of solution, its molarity is

Options

A. 0.8 M
B. 0.4 M
C. 0.2 M
D. 0.1 M

Answer

To find the molarity of the NaOH solution, we can follow these steps:

### Step 1: Determine the molar mass of NaOH
The molar mass of sodium hydroxide (NaOH) can be calculated by adding the atomic masses of its constituent elements:
- Sodium (Na): approximately 23 g/mol
- Oxygen (O): approximately 16 g/mol
- Hydrogen (H): approximately 1 g/mol

So, the molar mass of NaOH = 23 + 16 + 1 = 40 g/mol.

### Step 2: Calculate the number of moles of NaOH
Using the formula for moles:
\[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \]
Given that we have 8 grams of NaOH:
\[ \text{Number of moles} = \frac{8 \text{ g}}{40 \text{ g/mol}} = 0.2 \text{ moles} \]

### Step 3: Determine the volume of the solution in liters
The volume of the solution is given as 1 liter.

### Step 4: Calculate the molarity
Molarity (M) is defined as the number of moles of solute per liter of solution:
\[ \text{Molarity (M)} = \frac{\text{Number of moles}}{\text{Volume of solution (L)}} \]
Substituting the values we have:
\[ \text{Molarity (M)} = \frac{0.2 \text{ moles}}{1 \text{ L}} = 0.2 \text{ M} \]

### Final Answer
The molarity of the NaOH solution is **0.2 M**.

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