Spectrum #70: Order these by pH — the solution
The Spectrum puzzle from October 23, 2026: six things on one hidden scale, most acidic to most basic, with every figure and where the checks were best spent.
The puzzle
Order these by pH, most acidic at the top and most basic at the bottom. The board opened in this order:
- Vinegar
- Baking soda solution
- Stomach acid
- Bleach
- Black coffee
- Pure water
Nothing was in its place; Baking soda solution opened 3 places from home.
The walkthrough
The ends first. Stomach acid is the most acidic of the six at 1.5 and Bleach the most basic at 12.5. Anchor those and the middle four are what is left to place.
Where the scale splits. The widest gap is between Baking soda solution (9) and Bleach (12.5) — 3.5 apart. Everything above that line belongs on the most acidic side and everything below it on the most basic side, so sorting the six into those two groups is most of the puzzle.
The closest call. Stomach acid (1.5) and Vinegar (2.5) are only 1 apart — the pair that is a coin flip without the figures, and the place to spend a check: a check locks whatever is already right and leaves only the wrong tiles to swap.
The answer
| # | Most acidic to Most basic | Figure |
|---|---|---|
| 1 | Stomach acid | 1.5 |
| 2 | Vinegar | 2.5 |
| 3 | Black coffee | 5 |
| 4 | Pure water | 7 |
| 5 | Baking soda solution | 9 |
| 6 | Bleach | 12.5 |
Previous: Spectrum #69 (Thu, Oct 22) · Next: Spectrum #71 (Sat, Oct 24) · All Spectrum solutions
About Spectrum
Spectrum is Noggin’s daily ordering puzzle: six things, one hidden scale, three checks. Tiles in the right place lock green; the figures turn over when the board is done. How to play Spectrum, or play today’s.