Question

When an aqueous solution begins to freeze, the solid that separates out is usually pure ice.
If true enter 1, if false enter 0.

Answer 1

When an aqueous solution begins to freeze, the solid that separates out is usually pure ice.
In other words, no solute is dissolved in the ice that separates out.
However, this is an assumption and in some cases, there may be an appreciable concentration of solute in solid phase. An example is the solid solution system.