Special Sub-Topic: The Truth About Indicators
|Litmus is a common indicator used to tell whether something is an acid or a base. If you dip a piece of blue litmus paper into an acid, what color will it turn?|
Red. Acids are common in our lives: orange juice, sodas, and a lot of things we drink contain acids. But stronger acids can be dangerous, burning skin and corroding metal.
|If you dip a piece of red litmus paper into an acid, what color will it turn?|
None, it will stay red. Litmus usually comes as little strips of paper similar to pH test strips.
|Phenolphthalein is another acid-base indicator. Which of these is used as an abbreviation for this indicator?|
PHTH. Phenolphthalein is pronounced fee-nol-THAY-leen.
|If you were to drop some phenolphthalein into a base, what color would it turn?|
Purple-Pink. Bases are also common in our lives: shampoos, soaps and other cleaning products are all bases. But stronger bases like Drain-O can corrode skin.
|Goldenrod paper comes as little strips, similar to litmus. If you were to dip a piece of goldenrod paper in a base, what color would it turn?|
Red. You can buy goldenrod paper as full sheets at certain office stores. You can then mix baking soda and water and draw on the paper with cotton swabs dipped in the mixture.
|Now on to universal indicator. What color would this turn in a very strong acid?|
Red. An example of a very strong acid would be sulfuric acid (battery acid) or hydrochloric acid (stomach acid). They both have a pH of 1.
|What color would universal indicator turn if a substance was neutral?|
Green. While we say water is neutral, it is actually slightly basic, with a pH of 7.2.
|If you were to put some universal indicator in a very strong base, what color would it turn?|
Purple. Sodium Hydroxide (Lye) is a very strong base, with a pH of 14.
You should never mix cleaning products, because if one cleaner contains bleach and the other contains ammonia, the bases will react to produce harmful chlorine gas.
|One unconventional indicator is red cabbage juice. What color will this common liquid turn in a base?|
Blue-Green. Red cabbage juice is exactly what it says: the juice from a red cabbage!
|An indicator that you wouldn't find at home is Phenol Red. What color does this indicator turn in an acid?|
Yellow. Don't confuse Phenol Red with phenolphthalein! Phenol Red starts out red, while phenolphthalein starts clear.
There are also many other indicators that this quiz didn't cover, such as Methyl Orange.
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