Thursday, August 18, 2011

Chemistry Form 4: Chapter 7 - Strength of Acid

The strength of an acid depends on the degree of dissociation of the acid in water to produce hydrogen ions and anions. The pH of an acid solution depends on the concentration of hydrogen ions.

Strong Acid
Weak Acid
·     Strong acid have a higher degree of dissociation.
·     A strong acid is an acid which dissociates completely in water to produce a high concentration of hydrogen ions.
·     Thus, pH value for strong acid is lower than weak acid.

·     Weak acid have a lower degree of dissociation.
·     A weak acid is an acid which ionises partially in water to produce a low concentration of hydrogen ions. Only a part of the molecules ionises and the remaining still in covalent molecules.
·     Thus, pH value for weak acid is higher than strong acid.

Click on the diagram below to play!

Weak Acid

Strong Acid

Examples of strong acid
HCl      Hydrochloric acid     HNO3   Nitric acid
HBr      Hydrobromic acid     H2SO4   Sulfuric acid
HI      Hydroiodic acid      HClO4   Perchloric acid

Examples of weak acid


nadia said...

thanks cikgu , can I get physics note light & heat , quite difficult to understand . I understand much better because of your notes . I hope you won't stop . I loves your notes . It's very useful for rural area student like me . It's hard for student that can't afford to attend tuiton class . thank you :'D

Cikgu Wong said...

Dear Nadia,
You're welcome. Hope these notes will greatly help you. Please be patience as light and heat is on the way.