A is a binary compound of a univalent metal. When 1.422 g of A reacts completely with 0.321 g of sulphur in an evacuated and sealed tube, 1.743 g of white crystalline solid B produced, which produces a hydrated double salt C with `Al_(2)(SO_(4))_(3)`. Identfy A, B and C.

Explanation

To solve the problem step-by-step, we will identify the compounds A, B, and C based on the information provided.

### Step 1: Identify Compound A
Given that A is a binary compound of a univalent metal, we know that it consists of a metal (M) and oxygen. Since it is a binary compound and the metal is univalent, we can represent it as \( MO_2 \) (where M is the univalent metal and O is oxygen).

### Step 2: Write the Reaction
When A reacts with sulfur (S), it forms a white crystalline solid B. The reaction can be represented as:
\[ 2MO_2 + S \rightarrow MSO_4 \]
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