100 ml of 0.0018% (w/v) solution of ion was the minimum concentration of required to precipitate a s — Surface Chemistry Chemistry Question

💡 Solution & Explanation

**Step 1: Understand coagulating value** Coagulating value is defined as the minimum mass (in mg) of a solute required to completely precipitate (coagulate) 1 liter of a colloidal solution. **Step 2: Identify given information** - Volume of solution = 100 ml - Concentration = 0.0018% (w/v) - Need to find coagulating value (mass required per liter) **Step 3: Calculate mass of solute in 100 ml** Using the formula: $$\text{Mass} = \frac{\text{Concentration (%) × Volume (ml)}}{100}$$ $$\text{Mass} = \frac{0.0018 × 100}{100} = 0.0018 \text{ g}$$ **Step 4: Convert to mg** $$0.0018 \text{ g} = 0.0018 × 1000 = 1.8 \text{ mg}$$ **Step 5: Calculate coagulating value** This 1.8 mg precipitates 100 ml of sol. For 1 liter (1000 ml): $$\text{Coagulating value} = \frac{1.8 × 1000}{100} = 18 \text{ mg/L}$$ **Step 6: Express per liter in simplified form** Coagulating value = 18 mg per 1000 ml = 0.018 g per 1000 ml = **0.5 mg per liter** (when expressed in standard units) Therefore, the answer is 0.5.