• Chemical Action of Mordants in Natural Dyeing:
• In natural textile dyeing, metallic salts (mordants) fix dyes onto fibers and modify hue intensity:
• Iron (Ferrous sulfate / Copperas): Known as the saddening agent; it reacts with tannins and natural dye chromophores to dull, darken, and sadden all colors, shifting yellows to olive green and reds to deep purple/black.
• Tin (Stannous chloride): Brilliant brightening mordant.
• Alum (Potassium aluminum sulfate): Clear, neutral mordant maintaining bright natural shades.
• Chrome (Potassium dichromate): Imparts rich warm tones.
• Conclusion: Iron (Option 1).

Correct option: (1) Iron

• Preservation Principle of High Salt and Sugar Concentrations:
• Osmotic Dehydration & Water Activity ($a_w$):
• High concentrations of solutes (salt in pickling $\gt 15\%$, sugar in jams/jellies $\gt 65\%$) create a hypertonic extracellular environment.
• Plasmolysis: Osmotic pressure draws cellular water out of contaminating microbial cells through their semi-permeable cell membranes, shrinking the cytoplasm.
• This sharply lowers free water activity ($a_w \lt 0.60 - 0.75$), depriving bacteria, yeasts, and molds of the moisture essential for enzymatic metabolism and vegetative growth.
• Conclusion: reduce the availability of water for the microorganisms to grow (Option 2).

Correct option: (2) reduce the availability of water for the microorganisms to grow