The separation of two coloured substances was done by paper chromatography. The distances travelled — Practical Organic Chemistry and Purification Chemistry Question

💡 Solution & Explanation

**Step 1: Recall the Rf value formula** The retention factor (Rf) is calculated as: $$R_f = \frac{\text{Distance travelled by substance}}{\text{Distance travelled by solvent front}}$$ **Step 2: Calculate Rf for substance A** $$R_f(A) = \frac{2.08 \text{ cm}}{3.25 \text{ cm}} = 0.64$$ **Step 3: Calculate Rf for substance B** $$R_f(B) = \frac{1.05 \text{ cm}}{3.25 \text{ cm}} = 0.323$$ **Step 4: Find the ratio of Rf values** $$\frac{R_f(A)}{R_f(B)} = \frac{0.64}{0.323} = \frac{2.08}{1.05}$$ **Step 5: Calculate the final ratio** $$\frac{2.08}{1.05} = 1.98 ≈ 2.00$$ Therefore, the answer is **2.00**.