If I cool a solution containing 62 g of ethylene glycol in 250 g water to -9.3 °C, what mass of ice will separate out?
The amount of ice that will separate out is 50 g.
The formula for freezing point depression
#color(blue)(bar(ul(|color(white)(a/a)ΔT_text(f) = iK_text(f)bcolor(white)(a/a)|)))" "#
We can rearrange this expression to get
#b = (ΔT_text(f))/(iK_text(f)#
In this problem,
So, the allowed amount of water is
You started with 250 g of water, so the other 50 g must be present as ice.