Choose the incorrect statement.

Options

A. Sodium borohydride reacts very slowly with cold water
B. Sodium borohydride reacts violently with cold water to give `H_(2)(g)`
C. Solubility of sodium borohydride in water at `25^(@)C` is `10.05g//ml`
D. Melting point of sodium borohydride is `500^(@)C`

Explanation

To solve the question of identifying the incorrect statement regarding sodium boron hydride (NaBH4), we can follow these steps:

### Step 1: Analyze the Statements
We need to evaluate each statement provided about sodium boron hydride to determine which one is incorrect.

### Step 2: Evaluate the First Statement
The first statement is that sodium boron hydride reacts slowly with cold water.
- **Analysis**: This statement is true. Sodium boron hydride does react with cold water, but the reaction is slow and non-violent.

### Step 3: Evaluate the Second Statement
The second statement claims that sodium boron hydride reacts violently with cold water.
- **Analysis**: This statement is false. As established, sodium boron hydride reacts slowly and non-violently with cold water.

### Step 4: Evaluate the Third Statement
The third statement mentions that the solubility of sodium boron hydride in water at 25 degrees Celsius is known.
- **Analysis**: This statement is true. Sodium boron hydride does have a specific solubility in water at this temperature.

### Step 5: Evaluate the Fourth Statement
The fourth statement provides the melting point of sodium boron hydride, stating it is around 500 degrees Celsius.
- **Analysis**: This statement is also true. The melting point of sodium boron hydride is indeed around 400 to 500 degrees Celsius.

### Conclusion
After evaluating all statements, we find that the incorrect statement is the second one, which claims that sodium boron hydride reacts violently with cold water.

### Final Answer
The incorrect statement is: "Sodium boron hydride reacts violently with cold water."

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