Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A): Parchmentizing produces both opaque and transparent areas on cellulosic fabrics.
Reason (R): Acid resistant substance printed on the fabric prior to the acid treatment produces a design with both opaque and transparent areas.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

Parchmentization + acid-resistant resist printing is the standard industrial method used to manufacture patterned, stiff organdy fabrics.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Parchmentizing is a chemical finish where cotton (cellulosic) fabric is treated briefly with concentrated sulfuric acid, causing the cellulose to gelatinize and dry into a stiff, translucent, parchment-like state.

Step 2: Detailed Explanation:
Let us evaluate the statements:
1. Assertion (A) is Correct: Parchmentizing can be controlled to create patterns consisting of both opaque (original soft cotton) and transparent (acid-treated) areas. This is commonly known as "acid-print" or "organdy" finish.
2. Reason (R) is Correct: To achieve this patterned effect, a thick, acid-resistant chemical paste is printed onto the fabric in specific design areas. When the entire fabric is subsequent run through the sulfuric acid bath, the printed areas are protected from the acid and remain opaque. The unprotected areas are eaten away and gelatinized, becoming transparent.
3. Since the printing of the acid-resistant paste explained in (R) is the exact mechanism and explanation of how both opaque and transparent zones are formed in (A), (R) is the correct explanation of (A).

Step 3: Final Answer
The correct option is (A).