Correct statement about FeO at room temperature

Options

A. It is non-stoichiometirc and metal deficient
B. It is basic oxide
C. Its aqueous solution changes to `Fe(OH)_(3)` and then to `Fe_(2)O_(3),xH_(2)O` by atmospheric oxygen
D. It gives red colour with KCNS

Answer

To determine the correct statements about FeO (ferrous oxide) at room temperature, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding FeO**:
- FeO is known as ferrous oxide, where iron (Fe) is in the +2 oxidation state and oxygen (O) is in the -2 oxidation state.

2. **Analyzing Statement A**:
- **Statement**: "It is a non-stoichiometric and metal deficient."
- **Analysis**: FeO can exist in a non-stoichiometric form, such as Fe0.95O, indicating that it has a deficiency of iron. This statement is correct.

3. **Analyzing Statement B**:
- **Statement**: "It is a basic oxide."
- **Analysis**: Metal oxides are typically basic, and FeO reacts with water to form iron hydroxide (Fe(OH)2), which is a base. Therefore, this statement is also correct.

4. **Analyzing Statement C**:
- **Statement**: "Its aqueous solution changes to Fe(OH)3 and then to Fe2O3·XH2O by atmospheric oxygen."
- **Analysis**: When FeO is dissolved in water, it can form Fe(OH)2, which can further oxidize in the presence of atmospheric oxygen to form Fe(OH)3 and eventually Fe2O3·XH2O. This statement is correct.

5. **Analyzing Statement D**:
- **Statement**: "It gives red color with KSCN."
- **Analysis**: The red color reaction with potassium thiocyanate (KSCN) is characteristic of Fe3+ ions, forming ferric thiocyanate (Fe(SCN)3), not Fe2+. Therefore, this statement is incorrect.

### Conclusion:
The correct statements about FeO at room temperature are A, B, and C.

### Final Answer:
- **Correct Statements**: A, B, and C.

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