An inorganic Compound (A) has garnet red prismatic crystals. (A) is modertely soluble in water and dissolved in cold concentrated H_(2)SO_(4) to yield red crystal (B) . In presence of dilute H_(2)SO_(4) it converts a pungent gas (C ) into yellow turbidity (D) and converts a Suffocating gas (E) into a green solution (F). the gas (C ) and (E) also combine to produced the yellow turbidity (D) . With KI and starch in presence of dilute. H_(2)SO_(4) (A) and concentrated H_(2)SO_(4) Mixture used as a cleansing agent for glassware in the laboratory . identify (A) and explain the reactions.

Explanation

To solve the problem, we need to identify the inorganic compound (A) and explain the reactions that occur with it. Let's break down the information provided step by step.

### Step 1: Identify Compound (A)
The compound (A) is described as having garnet red prismatic crystals and being moderately soluble in water. Based on these characteristics, we can identify compound (A) as **Potassium Dichromate (K₂Cr₂O₇)**.

### Step 2: Reaction with Cold Concentrated H₂SO₄
When potassium dichromate (K₂Cr₂O₇) is dissolved in cold concentrated sulfuric acid (H₂SO₄), it forms red crystals of **Chromic Acid (CrO₃)**, which is our compound (B). The reaction can be summarized as:
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