Acid, bases and salt

• A pH tells how acidic or basic a substance is.
• The acidity or basicity of a solution can be described in terms of the hydrogen ion concentration.
• The concentration of hydrogen is represented in [] square brackets.
• Acids have Phs lower than 7
• Bases have a pH higher than 7. 
• A substance with a pH of 7 is neutral.
• Bases and acids react with each other to produce salt.
• If the [H+] concentration is greater than the [OH -] concentration then the substance is acidic.
• If the [OH -] concentration is greater than the [H+] concentration then the substance is basic.
• If the [OH -] concentration is the same or equal to the [H+] concentration then the substance is neutral.
• The litmus paper tells if the solution is acidic or basic. 
• The universal indicator ( universal paper) is the test used to find pH of a substance.
• The universal indicator paper is a mixture of acid-base indicators that show changes in colour at different Ph values. It is matched on the Ph scale. 
• The pH meter translates the concentration of H+ ion into an electric signal that is converted into a digital display or deflection on a meter.
• The Ph meter would give a more accurate reading than the universal indicator paper because it is able to give decimals. 
• The universal and litmus paper have indicators which is why they can change colours.
• Litmus changes to red in acid and blue in base.
• Phenolphthalein is colourless in acid and pink in base.
• Methyl orange is green in acid and yellow in a base.
• Bromothymol blue is yellow in acid and blue in a base.
• Screened Methyl orange is light red in acid and green in a base.
• Properties of acid are Corrosive, Sour taste, Ph less than 7, change blue litmus to red, and conduct electricity when in solution (aqueous).  
• Acids are substances that produce a greater concentration of hydrogen ions than hydroxide ions when dissolved in water or aqueous solutions. 
• The states acids exist as are Gases, liquids & solids.
• Examples of acids that exist as gasses are:

  CO 2  Carbon dioxide 

  SO2  Sulpher dioxide 

  SO3 Sulphite trioxide 

  NO2  Nitrogen oxide 
• Examples of acids that exist as liquids are HCL Hydrochloric acid

  HNO₃ Nitric acid 

  H₂SO₄ Sulphuric acid 
• Examples of acids that exists as solids are C6 H8 O7 Citric acid [ from citric fruits eg lime, orange, lemon]

  C6 H8 O6 Ascorbic acid ( vitamin C)

  C4H6O Tartaric acid ( from grapes)
• The two types of acids are mineral acids and organic acids.
• Mineral acids are obtained from minerals.
• Examples of mineral acids are H2SO4 sulfuric acid, hydrochloric acid HCl, H2CO3 carbonic acid, and HNO3 nitric acid.
• Organic acids are obtained from plants and animals.
• Examples of organic acids are CH3COOH ethanoic acid, C6H8O7 citric acid, C6H8O6 ascorbic acid, and C4H6O6 tartaric acid.
• A dilute solution for ethanoic acid is vinegar and it is made from apples - apple cider vinegar. 
• The concentrated solution contains more moles of solute per volume of solution than dilute ones. To go from a dilute to a concentrated solution you heat it.
• Basicity in acids is the number of H+ ions produced per molecule of acid when the acid dissolves in water. 
• A hydrogen ion can also be called a proton because after ionization only one proton is left. 
• Acids can be classified as monobasic or monoprotic, dibasic or diprotic, and tribasic or triprotic based on their basicity.
• Monobasic acids produce one hydrogen H+ per molecule when in solution.
• Hydrochloric acid (HCL), Nitric acid (HNO3), and CH3COOH Acetic or ethanoic acid are examples of monobasic acids.
• Sulphuric acid ( H2SO4), Carbonic acid (H2CO3) and Sulfurous acid (H2SO3)  are examples of dibasic acids.