Activity 6.2:
Aim: To determine acidic and alkaline substances in daily life using various indicators.
Materials: Blue litmus paper, red litmus paper, universal indicator, methyl orange, phenolphthalein, fizzy drink, dishwashing liquid, distilled water, syrup and salt water
Apparatus: Dropper, test tube, measuring cylinder, pH meter and test tube rack
Instruction
1. Add 2 ml of a fizzy drink, dishwashing liquid, distilled water, syrup and salt water into separate test tubes, then place them in a test tube rack.
2. Test these substances with blue litmus paper and red litmus paper.
3. Record your observations in a table.
4. Repeat steps 1 to 3 by replacing the litmus papers with universal indicator, methyl orange, phenolphthalein and pH meter.
Observation
Questions
1. What is the advantage of using universal indicator compared to litmus paper?
2. What is your inference on a substance that has a pH value of 7?
Answer:
1. Universal indicator can show the pH value of a substance. Litmus paper cannot show the pH value but it can determine whether a substance is acidic or alkaline.
2. The substance has a pH value of 7 because the substance is neutral.
Aim: To determine acidic and alkaline substances in daily life using various indicators.
Materials: Blue litmus paper, red litmus paper, universal indicator, methyl orange, phenolphthalein, fizzy drink, dishwashing liquid, distilled water, syrup and salt water
Apparatus: Dropper, test tube, measuring cylinder, pH meter and test tube rack
Instruction
1. Add 2 ml of a fizzy drink, dishwashing liquid, distilled water, syrup and salt water into separate test tubes, then place them in a test tube rack.
2. Test these substances with blue litmus paper and red litmus paper.
3. Record your observations in a table.
4. Repeat steps 1 to 3 by replacing the litmus papers with universal indicator, methyl orange, phenolphthalein and pH meter.
Observation
Questions
1. What is the advantage of using universal indicator compared to litmus paper?
2. What is your inference on a substance that has a pH value of 7?
Answer:
1. Universal indicator can show the pH value of a substance. Litmus paper cannot show the pH value but it can determine whether a substance is acidic or alkaline.
2. The substance has a pH value of 7 because the substance is neutral.