No change is an answer too
A student writes three strip results in a notebook. You read them and name the group.
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The idea
A neutral substance is neither acidic nor basic. Pure water, sugar solution and salt solution are neutral. They change neither blue litmus nor red litmus.
One strip that does not change is not enough. The strip only rules one group out. That means the liquid is not in that group.
| The strip did not change | Ruled out | Still possible |
|---|---|---|
| Blue litmus | acidic | basic, neutral |
| Red litmus | basic | acidic, neutral |
| Turmeric | basic | acidic, neutral |
Step 1 of 4
- Salt water. Blue litmus stays blue.
- Red litmus stays red too.
- Both papers: no change.
- Two unchanged papers: neutral.
Blue and red litmus both unchanged means neutral. Turmeric cannot tell acidic from neutral. This is because turmeric stays yellow in both.