Industrial chemicals – identity of ‘‘salt cake’’ In chemical processing terminology, the product commonly called salt cake is chemically represented by:

Introduction / Context:
Trade names like ‘‘salt cake’’ are frequently encountered in chemical industries, especially in glass, pulp and paper, and dye manufacture. Correctly identifying the chemical behind a trade name is essential for stoichiometric calculations, safety data sheets, and procurement.

Given Data / Assumptions:

• ‘‘Salt cake’’ is a well-known commodity chemical.
• Options list common sulfates with varying hydration and cations.
• We seek the most widely accepted industrial meaning of ‘‘salt cake.’’

Concept / Approach:
In industrial usage, ‘‘salt cake’’ refers to sodium sulfate (Na2SO4), historically produced in the Leblanc process and used in glass making and as a pulping aid. The term does not typically refer to calcium sulfate hemihydrate (plaster of Paris), magnesium sulfate (Epsom salt), or barium sulfate (blanc fixe).

Step-by-Step Solution:

Verification / Alternative check:
Materials handbooks and glass batch recipes consistently use ‘‘salt cake’’ to denote Na2SO4, confirming the selection.

Why Other Options Are Wrong:

• CaSO4·½H2O: Known as plaster of Paris, not salt cake.
• MgSO4: Epsom salt; different industrial uses.
• BaSO4: Barite or blanc fixe; a pigment/filler, not ‘‘salt cake.’’

Common Pitfalls:
Assuming all sulfates share the same trade name. In industry, each has distinct nomenclature linked to its applications and hydration state.

Final Answer:
Na2SO4