What is the function of Rochelle salt in Fehling's solution ?

Explanation

In alkaline medium `Cu^(2+)` ions get precipitate as `Cu(OH)_(2)`. To keep `Cu^(2+)` ions in solution in alkaline medium, Rochelle salt is added. The insoluble `Cu(OH)_(2)` first formed goes into solution due to the formation of a soluble complex between `Cu^(2+)` ions and tartrate ion as shown below:
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