CHEMISTRY FORM 4: CHAPTER 7

ACIDS

Acid is a chemical substance which ionizes in water to produce 

hydrogen ions, H⁺ or 

hydroxonium ions, H₃O⁺.

Properties of acid:

• React with bases to form salts and water
• React with reactive metals to form salts and hydrogen gas
• React with carbonates to form salts, water and carbon dioxide gas
• Turn moist blue litmus paper red
• Have pH values less than 7

Basicity of an acid is the number of ionisable of hydrogen atom per molecule of an 

acid molecule in an aqueous solution

1. 1. Monoprotic
   2. Diprotic
   3. Triprotic

BASES

1. Base is a substance which can react with an acid to form salt and water only.
2. Base that can dissolve in water is known as alkali.
3. An alkali is a substance which ionizes in water to produce free moving hydroxide

        ions, OH^-.

1. Alkaline properties:

• React with acids to form salts and water
• Produce ammonia gas when heated with ammonium salts
• Turn moist red litmus paper blue
• Have pH values more than 7