Question

5 gm of sodium chloride is dissolved in 2 liters of water. The salt concentration in water in ppm is

• A. 5000
• B. 10000
• C. 2500
• D. 2000

Hint:

Direct calculation: $\text{ppm} = \frac{\text{Grams} \times 1000}{\text{Liters}} = \frac{5000}{2} = 2500\text{ ppm}$.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Parts per million (ppm) is a standard water quality concentration unit representing milligrams of solute per liter of dilute aqueous solution (1 mg/L = 1 ppm).
Key Formula or Approach:
\[ \text{Concentration (ppm)} = \frac{\text{Mass of solute (mg)}}{\text{Volume of solution (litres)}} \]

Step 2: Detailed Explanation:
Given parameters:
- Mass of sodium chloride: \(m = 5\text{ g} = 5 \times 1000\text{ mg} = 5000\text{ mg}\)
- Volume of water: \(V = 2\text{ liters}\)
Calculating concentration in mg/L:
\[ \text{Concentration} = \frac{5000\text{ mg}}{2\text{ L}} = 2500\text{ mg/L} \]
Since \(1\text{ mg/L} = 1\text{ ppm}\) for dilute water solutions:
\[ \text{Salt concentration} = 2500\text{ ppm} \]

Step 3: Final Answer:
Thus, the salt concentration in water is 2500 ppm, corresponding to option (C).