Explain what an alkali is, list its properties, and identify five household products containing alkalis, including their safety warnings.

Here are the answers to Activity 6:

1. a) What is an alkali?
An alkali is a soluble base that dissolves in water to produce hydroxide ions ($\text{OH}^-$).

1. b) List some properties of alkalis.

• They turn red litmus paper blue.
• They have a pH value greater than 7.
• They feel slippery or soapy to the touch.
• They are corrosive and caustic, especially strong alkalis.
• They react with acids in a neutralization reaction to form a salt and water.

2. a) At home or in the supermarket, identify five products that contain alkalis.

1. Oven cleaner
2. Drain cleaner
3. Household bleach
4. Antacids
5. Ammonia-based window cleaner

2. b) Carefully read the label or list of ingredients on each of the products identified in a). Make a note of any safety warnings.

• Oven cleaner: Often contains sodium hydroxide. Warnings include "Causes severe skin burns and eye damage," "Harmful if swallowed," and "Keep out of reach of children."
• Drain cleaner: Often contains sodium hydroxide or potassium hydroxide. Warnings include "Corrosive," "Causes severe skin burns and eye damage," "May be fatal if swallowed," and "Do not mix with other chemicals."
• Household bleach: Contains sodium hypochlorite. Warnings include "Causes skin irritation," "Causes serious eye irritation," "Harmful to aquatic life," and "Do not mix with acids or ammonia."
• Antacids: Often contain magnesium hydroxide or aluminum hydroxide. Warnings typically advise not to exceed recommended dosage and to consult a doctor if symptoms persist. "Keep out of reach of children."
• Ammonia-based window cleaner: Contains ammonia. Warnings include "Causes skin irritation," "Causes serious eye irritation," "May cause respiratory irritation," and "Do not mix with bleach."

3. Make a poster for one of the products identified in a). Include the following information:
Let's choose Oven Cleaner for the poster.

a) The name of the product that contains the alkali
Oven Cleaner

b) The chemical name of the alkali and its formula
The alkali is Sodium hydroxide, with the chemical formula $\text{NaOH}$.

c) Whether the alkali is strong or weak
Sodium hydroxide is a strong alkali.

d) What the product is used for
Oven cleaner is used to remove baked-on grease, food residue, and grime from the interior surfaces of ovens.

e) Whether the product comes with a safety warning
Yes, oven cleaner comes with significant safety warnings due to its highly corrosive nature. These typically include warnings about severe skin burns, eye damage, and the danger if swallowed.