Industrial Materials (Paper Manufacturing) In manufacturing of commercial paper, wood pulp is treated with specific chemicals during the pulping and sizing stages. Which of the following combination best represents the conventional constituents used in the sulfite process for paper making?

Introduction / Context:
Paper manufacture is a classic process question asked in general science and industrial chemistry sections. Modern papermaking begins with fibrous raw material (usually wood) and relies on chemical pulping plus additives to convert lignocellulosic material into strong printable sheets. Understanding which reagents appear in standard processes helps distinguish core steps (pulping, bleaching, sizing) from secondary or unrelated operations.

Given Data / Assumptions:

• The stem refers to manufacturing paper from wood.
• Traditional sulfite pulping uses bisulphite chemistry based on calcium or other base cations.
• Sizing/resin additives are introduced to modify paper surface and internal bonding.

Concept / Approach:

The classic sulfite process cooks wood chips with an acidic solution of calcium bisulphite (often described historically as calcium hydrogen sulphite) to dissolve lignin and free cellulose fibers. Resin (with alum or other fixatives) functions as a sizing agent to improve water resistance and printability. While bleaching agents may appear later, they are not the defining pulping chemicals, and “sodium alone” or “bleaching powder alone” does not capture the standard route.

Step-by-Step Solution:

Identify pulping: sulfite pulping employs bisulphite ions derived from sulfur dioxide and base (here calcium) → calcium bisulphite.Relate to wording: “calcium, hydrogen sulphite” aligns with calcium bisulphite liquor historically named as such.Additives: resin sizing is a conventional papermaking additive.Choose the set that includes wood + calcium bisulphite + resin.

Verification / Alternative check:

Contrast with the kraft (sulfate) process, which uses sodium hydroxide/sodium sulfide, not bleaching powder. The option featuring calcium hydrogen sulphite and resin best matches sulfite practice plus sizing.

Why Other Options Are Wrong:

Wood and resin: Missing the pulping chemical.Wood, sodium and bleaching powder: Too vague; bleaching powder is not the core pulping liquor.Wood and bleaching powder: Bleaching is later; lacks pulping chemistry.Wood, sand and wax: Nonstandard for pulping.

Common Pitfalls:

Confusing bleaching chemicals with pulping liquors, and mixing kraft and sulfite terminologies.

Final Answer:

Wood, calcium, hydrogen sulphite and resin