What relative proportions of ethylene glycol `C_2H_6O_2` and water (by weight) should be mixed to form an antifreeze solution that will not start to freeze until the temperature reaches - `37^@C? K_f` for `H_2O` = 1.86.

Explanation

To solve the problem of determining the relative proportions of ethylene glycol (C₂H₆O₂) and water needed to create an antifreeze solution that does not freeze until -37°C, we will follow these steps:

### Step 1: Determine the change in freezing point (ΔTf)
The freezing point of pure water is 0°C. The solution should not freeze until -37°C, so:
\[ \Delta T_f = T_f (\text{pure water}) - T_f (\text{solution}) = 0°C - (-37°C) = 37°C \]

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