Question

Rochelle salt is chemically _______

• A. Sodium potassium chloride
• B. Sodium potassium tartrate
• C. Potassium sodium sulphate
• D. Sodium potassium carbonate

Hint:

Rochelle salt is sodium potassium tartrate, a double salt of tartaric acid.

Answer 1

The Correct Option is B

Concept:
Rochelle salt is a double salt. It contains sodium, potassium, and tartrate ions.

Step 1: Chemical name.
Rochelle salt is chemically known as sodium potassium tartrate.

Step 2: Formula.
Its chemical formula is commonly represented as: \[ KNaC_4H_4O_6 \cdot 4H_2O \]

Step 3: Why option (B) is correct.
The name sodium potassium tartrate directly matches the composition of Rochelle salt.

Step 4: Checking other options.
Sodium potassium chloride, potassium sodium sulphate, and sodium potassium carbonate are not Rochelle salt.

Step 5: Final answer.
Therefore, Rochelle salt is chemically sodium potassium tartrate. \[ \boxed{\text{Sodium potassium tartrate}} \]