What will be the molarity of a solution, which contains 5.85g of `NaCl(s)` per 500mL?

Options

A. `4 "mol" L^(-1)`
B. `20 "mol"L^(-1)`
C. `0.2"mol"L^(-1)`
D. `2 "mol"L^(-1)`

Explanation

To find the molarity of a solution containing 5.85 g of NaCl in 500 mL, we can follow these steps:

### Step 1: Write down the given information
- Mass of NaCl = 5.85 g
- Volume of solution = 500 mL = 0.5 L (since 1 L = 1000 mL)

### Step 2: Calculate the molar mass of NaCl
- Sodium (Na) has a molar mass of 23 g/mol.
- Chlorine (Cl) has a molar mass of 35.5 g/mol.
- Therefore, the molar mass of NaCl = 23 g/mol + 35.5 g/mol = 58.5 g/mol.

### Step 3: Calculate the number of moles of NaCl
Using the formula for number of moles:
\[ \text{Number of moles (n)} = \frac{\text{mass}}{\text{molar mass}} \]
Substituting the values:
\[ n = \frac{5.85 \text{ g}}{58.5 \text{ g/mol}} = 0.1 \text{ moles} \]

### Step 4: Calculate the molarity of the solution
Using the formula for molarity (M):
\[ M = \frac{\text{number of moles}}{\text{volume in liters}} \]
Substituting the values:
\[ M = \frac{0.1 \text{ moles}}{0.5 \text{ L}} = 0.2 \text{ moles/L} \]

### Final Answer:
The molarity of the solution is **0.2 moles/L**.

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