NCERT · Class 10 · Science · Acids, Bases and SaltsDescribe the properties of strong and weak acids and bases. Explain the pH scale and how it is used to measure the concentration of hydrogen ions in a solution.

Properties of Strong and Weak Acids and Bases

Strong Acids

• Strong acids are those that completely dissociate in water to produce hydrogen ions (H+).
• Examples of strong acids include HCl, HNO3, and H2SO4.
• Strong acids have a pH of less than 7.

Weak Acids

• Weak acids are those that only partially dissociate in water to produce hydrogen ions (H+).
• Examples of weak acids include acetic acid (CH3COOH) and citric acid (C6H8O7).
• Weak acids have a pH greater than 7.

Strong Bases

• Strong bases are those that completely dissociate in water to produce hydroxide ions (OH-).
• Examples of strong bases include NaOH and KOH.
• Strong bases have a pH greater than 7.

Weak Bases

• Weak bases are those that only partially dissociate in water to produce hydroxide ions (OH-).
• Examples of weak bases include ammonia (NH3) and methylamine (CH3NH2).
• Weak bases have a pH less than 7.

pH Scale

• The pH scale is a measure of the concentration of hydrogen ions in a solution.
• A pH of 7 is neutral, while a pH less than 7 is acidic and a pH greater than 7 is basic.
• The pH scale is logarithmic, meaning that each step up or down represents a tenfold change in concentration.

Using the pH Scale

• The pH scale is used to measure the concentration of hydrogen ions in a solution.
• It is an important tool in chemistry and is used in a variety of applications, including water treatment and food processing.