Assertion : The blue precipitate formed by the action of `K_(4)[Fe(CN)_(6)] on Fe^(3+)` and by that of `K_(2)[Fe(CN)_(6)]` on `Fe^(2+)` have the same composition
Reasion : `[Fe(CN)_(6)]^(3-) ` oxides `Fe^(2+)` to `Fe^(3-)` and itself gets reduced to `[Fe(CN)_(6)]^(4-)`.

Options

A. If both (A) and (B) are correct and (R ) is the correct explqanation of (A)
B. If both (A) and (B) are correct but (R ) is not the correct explqanation of (A)
C. If (A) is correct ,but (R ) is incorrect
D. If (A) is incorrect ,but (R ) is correct

Answer

To solve the question regarding the assertion and reason about the blue precipitate formed by the action of potassium ferrocyanide on ferrous and ferric ions, we can break it down into steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the blue precipitate formed by the action of \( K_4[Fe(CN)_6] \) on \( Fe^{3+} \) and by the action of \( K_2[Fe(CN)_6] \) on \( Fe^{2+} \) have the same composition.
- The blue precipitate formed in both cases is known as Turnbull's blue or Prussian blue, which has the formula \( Fe_3[Fe(CN)_6]_2 \).

2. **Analyzing the Reason**:
- The reason states that \( [Fe(CN)_6]^{3-} \) oxidizes \( Fe^{2+} \) to \( Fe^{3+} \) and itself gets reduced to \( [Fe(CN)_6]^{4-} \).
- This means that when \( K_2[Fe(CN)_6] \) reacts with \( Fe^{2+} \), the \( [Fe(CN)_6]^{3-} \) ion oxidizes the ferrous ion to ferric ion while being reduced to \( [Fe(CN)_6]^{4-} \).

3. **Chemical Reactions**:
- For \( K_4[Fe(CN)_6] \) with \( Fe^{3+} \):
\[ K_4[Fe(CN)_6] + Fe^{3+} \rightarrow Fe_3[Fe(CN)_6]_2 (blue \ precipitate) \]
- For \( K_2[Fe(CN)_6] \) with \( Fe^{2+} \):
\[ K_2[Fe(CN)_6] + Fe^{2+} \rightarrow [Fe(CN)_6]^{3-} + Fe^{3+} \]
- The \( [Fe(CN)_6]^{3-} \) then forms the same blue precipitate.

4. **Conclusion**:
- Both the assertion and reason are correct. The blue precipitate formed in both reactions has the same composition, and the reason correctly explains the oxidation-reduction process occurring in the reaction.

### Final Answer:
- The assertion is true, and the reason is true. Both statements are related to each other, confirming that the blue precipitate formed in both cases has the same composition.