So for starters, sodium carbonate is soluble in water. This is something you need to know, regarding salts preparations. All carbonates are insoluble except sodium carbonate, potassium carbonate and ammonium carbonate.
This means that crystallisation or simple distillation is more appropriate to get separate the sodium carbonate from the liquids.
However, crystallisation can't be used as we will lose the liquid. Therefore you will do simple distillation and then fractional distillation.
Hope this helps!
(You'd probably get marks for mentioning fractional distillation though.
In our school today we had a test on chemistry, and the last question was about separation techniques. The question was how to separate ethanol, limonene, and sodium carbonate. On the question, it said that sodium carbonate is solid in room temperature, and ethanol and limonene is in liquid form. They didn't say if sodium carbonate was soluble or insoluble, so I wrote use filtration to separate sodium carbonate from the other two liquids, and then use fractional distillation because limonene and ethanol has different boiling points. Is this correc?