Today we conducted experiments to find out the properties of alkalis.
Steps:
- Place a piece of blue litmus paper, red litmus paper and universal indicator paper on a white tile
- Use a dopper to carefully add a drop of dilute sodium hydroxide to all three strips of indicator.
- Repeat the experiment using dilute potassium hydroxide and ammonia water
For all 3 alkalis, the red litmus paper turned blue, while the blue litmus paper remained blue. For dilute hydroxide solution and sodium hydroxide solution, the universal indicator paper turned from green to bright violet. For ammonia, the universal indicator turned from green to bright blue.
Steps:
- Using a clean test tube, add dilute sodium hydroxide to the test tube to 2cm in height.
- Light the bunsen burner
- Carefully add 1 spatula of ammonium chloride to the test tube
- Warm the test tube gently over a bunsen flame
- Moisten a piece of red litmus paper and place it at the mouth of the test tube
- Gently fan some of the gas towards your nose
Observation
Effervescence is observed. Colorless and pungent gas evolved which turned damp/moist red litmus paper blue. Gas in ammonia gas.
Steps:
- Using a clean boiling tube, add dilute hydrochloric acid up to 2cm in height.
- Add 3 drops of universal indicator solution to the boiling tube
- Using a dropper, add 1 drop of dilute sodium hydroxide to the acid in the boiling tube and gently shake the boiling tube
