For Freundlich adsorption isotherm, a plot of log (x/m) (y - axis) and log p (x - axis) gives a stra — Surface Chemistry Chemistry Question
Question
For Freundlich adsorption isotherm, a plot of log (x/m) (y - axis) and log p (x - axis) gives a straight line. The intercept and slope for the line is 0.4771 and 2, respectively. The mass of gas, adsorbed per gram of adsorbent if the initial pressure is 0.04 atm, is ............ .
💡 Solution & Explanation
**Step 1: Recall the Freundlich adsorption isotherm equation** The Freundlich isotherm in logarithmic form is: $$\log\left(\frac{x}{m}\right) = \log k + n \log p$$ where x/m is mass of gas adsorbed per gram of adsorbent, k is the Freundlich constant, n is the slope, and p is pressure. **Step 2: Identify given values** - Intercept = log k = 0.4771 - Slope = n = 2 - Initial pressure = p = 0.04 atm **Step 3: Calculate the intercept value (k)** $$\log k = 0.4771$$ $$k = 10^{0.4771} = 3$$ **Step 4: Substitute values into the Freundlich equation** $$\log\left(\frac{x}{m}\right) = 0.4771 + 2 \times \log(0.04)$$ **Step 5: Calculate log(0.04)** $$\log(0.04) = \log(4 \times 10^{-2}) = \log 4 + \log 10^{-2}$$ $$= 0.6021 - 2 = -1.3979$$ **Step 6: Find x/m** $$\log\left(\frac{x}{m}\right) = 0.4771 + 2(-1.3979)$$ $$= 0.4771 - 2.7958 = -2.3187$$ $$\frac{x}{m} = 10^{-2.3187} = 0.048 \times 10^3 = 48$$ Therefore, the answer is 48.00.