A metallic element is converted into a compound 'A' after a series of reactions. Compound 'A' turns red litmus blue. 'A' on reaction with another compound B which turns blue litmus red gave a compound 'C' which responded to litmus test like compound 'B'. 'C' on further reaction with 'A' gave a compound 'D' Which did not respond to litmus test. Identify the correct sequence of steps for the formation of A, B, C and D.
(a) `NaOH + H_(2)SO_(4) rarr NaHSO_(4) + H_(2)O`
(b) ` 4Na + O_(2) rarr 2Na_(2)O`
(c) `NaHSO_(4) + NaOH rarr Na_(2)SO_(4) + H_(2)O`
(d) `Na_(2)O + H_(2)O rarr 2NaOH`

Options

A. acbd
B. bcad
C. bdac
D. dbac

Explanation

To solve the problem, we need to identify the compounds A, B, C, and D based on the information given. Let's break down the steps systematically.

### Step 1: Identify Compound A
- The problem states that a metallic element is converted into a compound 'A' after a series of reactions.
- Compound 'A' turns red litmus blue, indicating that it is a base.
- A common metallic element that forms a base is sodium (Na), which can form sodium hydroxide (NaOH) when it reacts with water.

**Reaction:**
\[ 2Na + 2H_2O \rightarrow 2NaOH + H_2 \]
Thus, we can assume:
- **Compound A = NaOH**

### Step 2: Identify Compound B
- The problem states that compound 'A' (NaOH) reacts with another compound 'B' that turns blue litmus red.
- This indicates that compound 'B' is an acid. A common acid that fits this description is sulfuric acid (H₂SO₄).

**Reaction:**
\[ NaOH + H_2SO_4 \rightarrow NaHSO_4 + H_2O \]
Thus, we can assume:
- **Compound B = H₂SO₄**

### Step 3: Identify Compound C
- The reaction of 'A' (NaOH) with 'B' (H₂SO₄) produces compound 'C', which responds to the litmus test like compound 'B'.
- Since 'B' is an acid, and 'C' behaves like an acid, we can deduce that compound 'C' is sodium hydrogen sulfate (NaHSO₄).

**Reaction:**
\[ NaOH + H_2SO_4 \rightarrow NaHSO_4 + H_2O \]
Thus, we can assume:
- **Compound C = NaHSO₄**

### Step 4: Identify Compound D
- The problem states that 'C' (NaHSO₄) reacts with 'A' (NaOH) to give a compound 'D' which does not respond to the litmus test.
- This indicates that 'D' is neutral and does not exhibit acidic or basic properties. The reaction of sodium hydrogen sulfate with sodium hydroxide can produce sodium sulfate.

**Reaction:**
\[ NaHSO_4 + NaOH \rightarrow Na_2SO_4 + H_2O \]
Thus, we can assume:
- **Compound D = Na₂SO₄**

### Summary of Compounds
- **A = NaOH** (sodium hydroxide)
- **B = H₂SO₄** (sulfuric acid)
- **C = NaHSO₄** (sodium hydrogen sulfate)
- **D = Na₂SO₄** (sodium sulfate)

### Correct Sequence of Steps
1. **(b)** \( 4Na + O_2 \rightarrow 2Na_2O \) (Formation of sodium oxide)
2. **(d)** \( Na_2O + H_2O \rightarrow 2NaOH \) (Formation of compound A)
3. **(a)** \( NaOH + H_2SO_4 \rightarrow NaHSO_4 + H_2O \) (Formation of compound C)
4. **(c)** \( NaHSO_4 + NaOH \rightarrow Na_2SO_4 + H_2O \) (Formation of compound D)

### Final Answer
The correct sequence of steps for the formation of A, B, C, and D is:
1. **(b)**
2. **(d)**
3. **(a)**
4. **(c)**