Question

Using the given figure, the ratio of \(R_f\) values of sample A and sample C is x × 10^–2. Value of x is __________.

Answer 1

Correct Answer: 50

The \(R_f\) value in chromatography is given by:
\[R_f = \frac{\text{Distance traveled by the sample spot}}{\text{Distance traveled by the solvent front}}.\]
Step 1: Calculate \(R_f\) for sample \(A\)
For sample \(A\):
\[R_f(A) = \frac{\text{Distance traveled by sample } A}{\text{Distance traveled by solvent front}} = \frac{5}{12.5}.\]
\[R_f(A) = 0.4.\]
Step 2: Calculate \(R_f\) for sample \(C\)  
For sample \(C\):
\[R_f(C) = \frac{\text{Distance traveled by sample } C}{\text{Distance traveled by solvent front}} = \frac{10}{12.5}.\]
\[R_f(C) = 0.8.\]
Step 3: Calculate the ratio of \(R_f\) values
The ratio of \(R_f\) values for sample \(A\) and sample \(C\) is:
\[\text{Ratio} = \frac{R_f(A)}{R_f(C)} = \frac{0.4}{0.8} = 0.5.\]
Expressing the ratio as \(x \times 10^{-2}\):
\[\text{Ratio} = 50 \times 10^{-2}.\]
Final Answer: \(x = 50\).