Question

Arrange the following processes used in manufacturing viscose rayon in correct sequence:
(A). Xanthating
(B). Shredding
(C). Steeping
(D). Dissolving
(E). Ageing
(F). Filtering
(G). Spinning
Choose the correct answer from the options given below:

• A. (A), (B), (C), (D), (F), (E), (G).
• B. (E), (A), (G), (F), (B), (C), (D).
• C. (C), (B), (E), (A), (D), (F), (G).
• D. (C), (B), (D), (A), (F), (E), (G)

Hint:

To remember the viscose sequence easily:
You must first "Steep" (C) and "Shred" (B) the pulp, then chemically alter it via "Xanthating" (A) before "Dissolving" (D) it into a liquid and finally "Spinning" (G) it into yarn.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Viscose rayon is a regenerated cellulose fiber. Its manufacturing process involves converting raw wood pulp (insoluble cellulose) into a soluble chemical derivative (viscose) before regenerating it back into pure cellulose filaments.

Step 2: Detailed Explanation:
The standard sequential industrial steps are:
1. Steeping (C): Wood pulp sheets are steeped in sodium hydroxide (\(NaOH\)) to form alkali cellulose.
2. Shredding (B): The alkali-cellulose sheets are shredded into fluffy, crumb-like particles.
3. Ageing (E): The crumbs are stored in contact with air to allow controlled oxidation (reducing polymer chain length).
4. Xanthating (A): The aged crumbs are reacted with carbon disulfide (\(CS_2\)) to form sodium cellulose xanthate, which is a yellow-orange soluble compound.
5. Dissolving (D): The xanthate is dissolved in a dilute caustic soda solution to form a thick, viscous liquid called "viscose."
6. Filtering (F): The viscose is filtered to remove impurities and deaerated to prevent air bubbles during extrusion.
7. Spinning (G): The viscose is pumped through spinnerets into an acid bath, which regenerates (coagulates) the cellulose into solid filaments.
This sequence corresponds to: (C), (B), (E), (A), (D), (F), (G).

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