Which of the following statements is INCORRECT regarding caustic potash, `KOH :`

Options

A. It is prepared by the electrolysis of an aqueous solution of KCl.
B. It is used for the absorption of gases like `CO_(2),SO_(2)` etc. in eudiometry.
C. White phosphorus undergoes disproportionation reaction with its aqueous solution, when boiled.
D. Commercially, it can be prepared by Le`-`Blanc process, but not by Solvay's process.

Explanation

To determine which statement regarding caustic potash (KOH) is incorrect, let's analyze each statement step by step.

### Step 1: Analyze Statement A
**Statement A:** "It is prepared by the electrolysis of an aqueous solution of KCl."

- **Explanation:** This statement is correct. Caustic potash (KOH) can indeed be produced through the electrolysis of an aqueous solution of potassium chloride (KCl). During this process, potassium ions (K⁺) and hydroxide ions (OH⁻) are formed, which combine to produce KOH.

### Step 2: Analyze Statement B
**Statement B:** "It is used for the absorption of gases like CO2, SO2, etc. in eudiometry."

- **Explanation:** This statement is also correct. KOH is used to absorb gases such as carbon dioxide (CO2) and sulfur dioxide (SO2) in eudiometry. The reaction of KOH with CO2 produces potassium carbonate (K2CO3) and water (H2O), confirming its use in gas absorption.

### Step 3: Analyze Statement C
**Statement C:** "White phosphorus undergoes disproportionation reaction with its aqueous solution when boiled."

- **Explanation:** This statement is correct. White phosphorus (P4) can undergo a disproportionation reaction when boiled in an aqueous solution, leading to the formation of phosphoric acid and phosphine. This confirms that the statement is accurate.

### Step 4: Analyze Statement D
**Statement D:** "Commercially it can be prepared by Leblanc process but not by Solvay's process."

- **Explanation:** This statement is incorrect. The Leblanc process is primarily used for the production of sodium carbonate (Na2CO3) and does not yield KOH. The Solvay process is also not used for KOH production. KOH is typically produced through the electrolysis of KCl or by other methods, but not through the Leblanc or Solvay processes.

### Conclusion
The incorrect statement regarding caustic potash (KOH) is **Statement D**.

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