Metal sulphate `(A) overset(Heat) to "oxide"(B)+gas(C)+gas(D)overset(Cr_(2)O_(7)^(2-)//H^(+))to`Green solution `underset(Excess)overset(Na_(2)O_(2))to underset("yellow solution")(E)`
Compound A, B, C, D are E are respectively:

Options

A. `FeSO_(4),Fe_(2)O_(3),SO_(3),SO_(2),Na_(2)CrO_(4)`
B. `Al_(2)(So_(4))_(3),Al_(2)O_(3),SO_(3),SO_(2),Na_(2)CrO_(4)`
C. `CuSO_(4),CuO,SO_(3),SO_(2),NaCrO_(4)`
D. `ZnSO_(4),ZnO_(2),SO_(3),SO_(2),Na_(2)CrO_(4)`

Explanation

To solve the problem step by step, we will analyze the reactions and identify the compounds involved.

### Step 1: Identify Compound A
The question states that a metal sulfate (A) decomposes upon heating to produce an oxide (B), gas (C), and gas (D).

**Solution:**
The metal sulfate that commonly decomposes under heat is **ferrous sulfate (FeSO4)**.

**Hint:** Look for a metal sulfate that is known to decompose upon heating.

### Step 2: Identify Compound B
Upon heating, ferrous sulfate decomposes to produce an oxide.

**Solution:**
The decomposition of FeSO4 results in the formation of **iron(III) oxide (Fe2O3)**.

**Hint:** Consider the common oxides formed from the decomposition of metal sulfates.

### Step 3: Identify Gases C and D
The decomposition of FeSO4 also produces gases.

**Solution:**
The gases produced during the decomposition of FeSO4 are **sulfur trioxide (SO3)** and **sulfur dioxide (SO2)**.

**Hint:** Think about the gases typically released during the thermal decomposition of sulfates.

### Step 4: Reaction with Dichromate Ion
The next part of the question mentions that the product reacts with dichromate ions in an acidic medium to produce a green solution.

**Solution:**
When iron(III) oxide (Fe2O3) is treated with dichromate ions (Cr2O7^2-) in an acidic medium, it forms **Cr3+ ions**, which give a green solution.

**Hint:** Remember that Cr3+ ions are typically associated with green solutions in aqueous chemistry.

### Step 5: Reaction with Sodium Peroxide
The final step involves the reaction with excess sodium peroxide (Na2O2), leading to the formation of a yellow solution.

**Solution:**
In the presence of excess sodium peroxide, the chromium ions (Cr3+) are oxidized to form **sodium chromate (Na2CrO4)**, which is a yellow solution.

**Hint:** Consider the oxidation states of chromium and how they change in the presence of strong oxidizing agents.

### Final Summary of Compounds
- Compound A: **FeSO4** (ferrous sulfate)
- Compound B: **Fe2O3** (iron(III) oxide)
- Compound C: **SO3** (sulfur trioxide)
- Compound D: **SO2** (sulfur dioxide)
- Compound E: **Na2CrO4** (sodium chromate)

### Complete Answer
The compounds A, B, C, D, and E are respectively:
- A: FeSO4
- B: Fe2O3
- C: SO3
- D: SO2
- E: Na2CrO4