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35 % (W/W) solution of ethylene glycol in water, an anti-freezer used in automobiles in radiators as a coolant. It lowers freezing point of water to -17.6 °C. Calculate the mole fraction of the components. |
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Answer» 35% (W/W) means 100 g solution contains 35 g ethylene glycol (CH2OH-CH2OH) and 65 g H2O. Molar mass of water = 18 g mol-1 Molar mass of ethylene glycol (CH2OHCH2OH) = 62 g mol-1 Number of moles of water = n1 = \(\frac{65}{18}\) = 3.611 mol Number of moles of ethylene glycol = n2 = \(\frac{35}{62}\)= 0.5645 mol Total moles = n = n1 + n2 = 3.611 + 0.5645 = 4.1755 mol Mole fraction of ethylene glycol = x2 = \(\frac{n_2}{n_1}\) = \(\frac{0.5645}{4.1755}\) = 0.1352 ∴ Mole fraction of water = 1 – x2 = 1 – 0.1352 = 0.8648 ∴ Mole fraction of water = 0.8648 Mole fraction of ethylene glycol = 0.1352 |
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