Complex sentence: Tartaric acid in Fehling's solution is used to prevent copper (II) ions from reacting with the hydroxide ions present, by heating this solution with glucose and heating copper (I) oxide precipitates.
Split into simpler sentences: Tartaric acid in Fehling's solution is used to prevent copper (II) ions from reacting with the hydroxide ions present. By heating this solution with glucose and heating, copper (I) oxide precipitates.