The solution having lowest molar concentration is

Options

A. 1.0N HCl
B. `0.4 N H_(2)SO_(4)`
C. `0.1N Na_(2)CO_(3)`
D. 1N NaOH

Answer

To determine which solution has the lowest molar concentration among the given options, we need to convert the normality of each solution to molarity. Here’s a step-by-step solution:

### Step 1: Understanding Normality and Molarity
Normality (N) is defined as the number of equivalents of solute per liter of solution. Molarity (M) is defined as the number of moles of solute per liter of solution. The relationship between normality and molarity can be expressed as:
\[ \text{Normality} = n \times \text{Molarity} \]
where \( n \) is the number of equivalents (n-factor).

### Step 2: Calculate Molarity for Each Option
We will calculate the molarity for each solution using the formula:
\[ \text{Molarity} = \frac{\text{Normality}}{n} \]

1. **Option 1: 0.1 N HCl**
- n-factor of HCl = 1 (since it donates 1 H+ ion)
- Molarity = \( \frac{0.1}{1} = 0.1 \, M \)

2. **Option 2: 0.4 N H2SO4**
- n-factor of H2SO4 = 2 (since it donates 2 H+ ions)
- Molarity = \( \frac{0.4}{2} = 0.2 \, M \)

3. **Option 3: 0.1 N Na2CO3**
- n-factor of Na2CO3 = 2 (total positive charge = 2 from Na+, total negative charge = 2 from CO3^2-)
- Molarity = \( \frac{0.1}{2} = 0.05 \, M \)

4. **Option 4: 1 N NaOH**
- n-factor of NaOH = 1 (since it donates 1 OH- ion)
- Molarity = \( \frac{1}{1} = 1 \, M \)

### Step 3: Compare Molarities
Now we have the molarities for each option:
- Option 1: 0.1 M
- Option 2: 0.2 M
- Option 3: 0.05 M
- Option 4: 1 M

### Step 4: Identify the Lowest Molar Concentration
From the calculated molarities, we can see that:
- The lowest molar concentration is **0.05 M** from **0.1 N Na2CO3**.

### Conclusion
The solution with the lowest molar concentration is **0.1 N Na2CO3**.

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