give the tests to identify acids and bases
Answers
Answer:
- Litmus test
- Phenolphthalein
- Methyl Orange
Answer:
1..Litmus paper is used to determine whether an aqueous solution is acidic (pH<7.0) or basic/alkaline (pH>7.0) in nature.
Blue litmus paper turns to red in acidic medium (pH<7.0).
Red litmus paper turns to blue in alkaline/basic medium (pH>7.0).
No change in color of litmus paper is seen at neutral pH (pH 7.0).
2. Various Indicators or dyes such as phenol- phthalein, topfer’s indicator, phenol red, methyl orange, thymol blue, bromophenol blue, etc. are used to find out acidic pH or basic/alkaline pH. The indicators show different colors in acidic and basic media, e.g. methyl orange and topfer’s indicator turn red in acidic medium and phenolphthalein turns pink in alkaline medium.
3. pH paper strips are used to determine pH. A drop of solution is kept on the pH paper strip and the color developed on the strip is matched with the provided standard color-pH chart to find out the pH. Although determination of pH by this method is easy and quick, but not accurate. It gives fairly accurate value.
4...Electronic (Digital) pH meter is used for accurate measurement of pH. The basic components of an electronic pH meter are indicator electrode (special glass electrode sensitive to H+), a reference (or calomel) electrode and potentiometer