Acid bases n salts


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Acid bases n salts

  1. 1. Acids Bases And Salts Chapter-2
  2. 2. Acids  An acid is a substance that produces hydrogen ions (H+) when placed in aqueous solution .  When acids/ ionic compounds are dissolved in water, the ions split apart from each other (Dissociation)
  3. 3. Properties of Acids Most acids…  Taste sour  React with many metals to form H2 gas  Are corrosive • Zinc Metal + Hydrochloric Acid  ?? Zn (s) + 2 HCl (aq)  H2 (g) + ZnCl2 (aq)
  4. 4. • Acetic Acid  Vinegar  Used as a preservative • Carbonic Acid ( H2CO3) or Phosphoric Acid (H3PO4)  Found in soft drinks • Hydrochloric Acid (HCl)  Found in our stomachs- aids in food digestion • Citric Acid  Found in citrus fruits • Used as a preservative • Lactic Acid  Found in yogurt  Produced by our muscles when they are overworked COMMON ACIDS
  5. 5. BASES • A base is a substance that produces hydroxide ions (OH-) when placed in water. • When bases/ ionic compounds are dissolved in water, the ions split apart from each other. (Dissociation)
  6. 6. PROPERTIES OF BASES Most bases… Taste bitter Feel slippery Are corrosive (appears to “eat away” materials while reacting) Have a chemical formula that ends with OH
  7. 7. COMMON BASES o Ammonia • Cleaners and fertilizers  Sodium hydroxide • Used in soaps and drain cleaners  Magnesium hydroxide • An ingredient found in antacids
  8. 8. STRONG/WEAK ACIDS & BASES  When a strong acid/base dissolves in water, nearly all of the acid/base molecules will dissociate into ions  The greater the ability to dissociate, the more potential the acid or base has for being dangerous because there are more ions available to react  When a weak acid/base dissolves in water, only a small fraction of the acid/base molecules dissociate (dissociate partially)  With less ions in solution, there is less potential for danger because there are less ions available to react Hydrogen Hydrogen
  9. 9. STRONG/WEAK ACIDS EXAMPLES Strong Acids 1. HNO3 – nitric acid 2. H2SO4 – sulfuric acid – battery acid 3. HCl – hydrochloric acid – stomach acid Weak Acids: 1. H3C6H5O7 –citric acid –citrus fruits 2. HC2H3O2 – acetic acid – vinegar
  10. 10. STRONG/WEAK BASES EXAMPLES  Strong Bases: 1. NaOH – sodium hydroxide 2. Any alkali or alkaline earth metal with OH- (i.e. KOH – potassium hydroxide)  Weak Bases: 1. Al(OH)3 – aluminum hydroxide – often found in deodorants 2. NH4OH – ammonium hydroxide (ammonia) –used in many cleaning products
  11. 11. CONCENTRATED AND DILUTE SOLUTION • CONCENTRATED SOLUTION – The solution which contain less amount of water [as a solvent] is known as CONCENTRATED SOLUTION . • DILUTE SOLUTION –The solution which contain more amount of water [as a solvent ]is known as DILUTE SOLUTION .
  12. 12.  Indicators are used to determine if a substance is an acid or a base  An indicator changes a specific color when in the presence of an acid or a base  Litmus Paper: indicator made of a special filter paper that contains dyes extracted from lichens (the crusty “stuff” that grows in rocks) Blue litmus turns red in an ACID Red litmus turns blue in a BASE INDICATORS
  13. 13. PH SCALE The pH scale can also help us classify solutions as acids or bases pH is a measure of the amount of H+ ions in a solution (potential hydrogen)  The more H+ ions, the lower the pH, the more acidic the solution
  14. 14. NEUTRALIZATION Neutralization is a chemical reaction between an acid and a base that takes place in a water solution When acids and bases react, the H+ ions from the acid react with the OH- ions from the base to form HOH (H2O - water!) The overall pH becomes “neutral”
  15. 15. SALTS The ions that are left behind after the H+ and OH- ions form water, combine to form a salt. A salt is a compound that forms when the negative ions from the acid combine with the positive ions from the base. Acid + Base  Water + Salt HCl(aq) + KOH(aq)  H2O(l) + KCl(aq)
  16. 16. Made By :- AyUsH gUpTa CLASS :- X-B ROLL NO. :- 06