If I had to start over and buy chemical compounds for preparedness in order of priority, this is the list.
Baking soda (sodium bicarbonate). Easily the most versatile chemical compound in existence. Over 100 uses spanning cooking, cleaning, hygiene, first aid, fire suppression, and odor control. Indefinite shelf life.
Calcium hypochlorite (pool shock). Purifies water and lets you mix a fresh bleach-like solution any time you need one. Regular bleach degrades in 6 to 12 months. Sealed calcium hypochlorite lasts 10 years and gives you fresh sanitizer on demand.
Hydrogen peroxide. Shorter shelf life (about 6 months once opened) but incredibly useful while it's active. Wound cleaning, surface disinfecting, oxygen release for stuck drains, plant root protection. Worth rotating through.
White vinegar (acetic acid). Indefinite shelf life. Disinfects, preserves food, removes rust, kills weeds, breaks down hard water deposits. The list of uses doesn't stop.
Salt. Pure sodium chloride. Indefinite shelf life. Food preservation, curing, wound saline, electrolyte balance, livestock, ice melt, and dozens more uses.
A few things worth knowing:
You don't need to buy everything at once. The chemical compounds book I'm writing has a phased purchasing chapter that breaks it into 4 budget-friendly waves so you build up without breaking the bank.
These five alone replace dozens of single-purpose products you're probably buying separately. Real money saved, less storage space taken, longer shelf life across the board.
The book is over 200 pages with 100 recipes. Still fact checking. Pre-orders coming when it's ready.