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प्रश्न
Ethylene glycol is used as an antifreeze agent. Calculate the amount of ethylene glycol to be added to 4 kg of water to prevent it from freezing at -6°C. (Kf for H2O = 1 .85 K mole-1 kg)
उत्तर
Depression in freezing point, `ΔT_f = (1000 xx K_f xx w)/(W xxM )`
Given , W = 4 kg = 4000 g
Kf = 1.85
ΔTf = 0 -(-6°) = 6° C
Mol. mas (M) of ethylene glycol CH2 OH - CH2 OH = 62
∴ Amount of ethylene glycol required,
`w = (MxxW xx Delta T_f)/(1000 xx K_f)`
`=(62xx4000xx6)/(1000xx1.85) = 804.32`g.
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