Sodium potassium tartrate is a double salt of tartaric acid with the chemical formula C4H4O6KNa·4H2O.  It is also referred to as Rochelle salt or potassium sodium tartrate in some circles.

It is a colourless to white crystalline powder with a cool and saline taste that can be found in many foods. It has a pH range of 6.5 to 8.5, making it a basic solution. It has a significant piezometric effect, which makes it extremely useful in sensitive vibrational and acoustic devices, among other applications.

Sodium Potassium Tartrate is made in the following ways:

Step-by-step procedure for the preparation of sodium potassium tartrate.

The following equipments and ingredients are required:

• 500 g of sodium bicarbonate (baking soda)
• Potassium bitartrate in the amount of 200 g
• Pyrex storage container
• pyrex measuring cup with a capacity of 500 mL
• spoon with a capacity of 2 mL
• Filtering coffee with a coffee filter
• Jar with a tight-fitting lid
• Oven
• To stir, use a spoon.
• Saucepan, Filter paper, and Water

Sodium bicarbonate is converted to sodium carbonate in the first step, which includes the following steps:

• Add 500 g of sodium bicarbonate to a pyrex container and shake well (baking soda).
• Preheat the oven to 65 degrees Celsius for one hour.
• Repeat the preceding step for temperatures of 175°C and 230°C.
• Remove the baking container from the oven and allow it to cool to room temperature before using.
• Transfer the washing soda (sodium carbonate) to a container with a tight-fitting lid.
• Potassium bitartrate (cream of tartar) reacts with sodium carbonate to produce sodium potassium tartrate (Rochelle salt) in step two.
•  250mL of water should be added to it. 200 g of potassium bitartrate should be suspended in the beaker containing water.
• Fill a saucepan halfway with water, then add the beaker and heat it up.
• Increase the heat until you can see the outer water simmering.
• To the beaker, add 2.5 mL of the washing soda that was obtained from the previous experiment. Stir it thoroughly, and the solution will begin to bubble.
• Continue to add sodium carbonate to the solution until no more bubbles can be seen in the solution.
• Once there are no bubbles forming in the solution, filter it through filter paper to remove any remaining particles.
• You can also filter the hot solution through a coffee filter if you prefer.
• By heating the solution, it can be evaporated and concentrated to 400 mL.
• Allow the filtrate to cool before storing it in a cool place.
• After a few days of storing, use the decantation process to collect the crystals that have resulted from the storage.
• To dry the crystals, place them between two sheets of filter paper.
• The amount of sodium potassium tartrate (Rochelle salt) obtained is approximately 210 g.
• The Chemical Reaction That Takes Place During the Production of Rochelle Salt, The process of converting sodium bicarbonate to sodium carbonate:

2NaHCO3 + CO2 + H2O  →  Na2CO3 + CO2 + H2O

• After reacting, sodium carbonate & potassium bitartrate (cream of tartar), sodium potassium tartrate (Rochelle salt) is formed.

KHC4H4O6 + Na2CO3 →  C4H4O6KNa4.H2O

Sodium Potassium Tartrate’s Physical and Chemical Characteristics:

C4H4O6KNa4.H2O

• Sodium potassium tartrate (Rochelle salt)  288.2 g Molecular weight/molar mass
• Density 1.79 g/cm3 is the density of air in a cubic centimetre.
• 220 degrees Celsius is the boiling point.
• 75 degrees Celsius is the melting point.

Sodium Potassium Tartrate’s Chemical Formulation

• The structure of sodium potassium tartrate is depicted in the illustration above. Sodium potassium tartrate has the chemical formula C4H4O6KNa4.H2O, and it contains ten oxygen atoms, twelve hydrogen atoms, four carbon atoms, one potassium atom, and one sodium atom. 
• Sodium Potassium Tartrate (C4H4O6KNa4.H2O) has a variety of applications.
• Sodium potassium tartrate is a laxative that is used to relieve constipation.
• It is used in the silvering of mirrors, among other things.
• Fehling’s solution contains this substance as one of its components.
• Electroplating is a process that makes use of this substance.
• It is used in the production of cigarette paper.
• It is employed in the dissolution of emulsions.
• It is one of the components of the Biuret reagent, which is used to determine the concentration of protein.
• It contributes to the preservation of alkaline pH.
• It is a common precipitant in protein crystallography, and it has a variety of applications.

CONCLUSION:

We conclude that potassium tartrate, also known as Rochelle salt, is a double salt of tartaric acid and is therefore a double salt of potassium. It was created for the first time in the year 1672 by an apothecary from La Rochelle, France, named Pierre Seignette. Rochelle salt is a white crystalline powder with a slightly bitter taste that is found in small amounts. 6.5–8.5 is the pH range for this solution. A by-product of the wine industry, crude Cream of Tartar is used to create it through the reaction of Sodium Hydroxide with the cream of tartar. Both alcohol and ether are almost completely insoluble in it.