The Chemical Rainbow-Acids and Bases

The Chemical Rainbow-Acids and Bases

->What is the use of sanitary cleaner like Harpic?

   To clean toilet/floor stains etc.

->Haven’t you been advised by your elders not to touch this liquid? Why?

Yes, because it harms the skin if it comes in contact with our skin.

Acids are substances which produce hydrogen ions when dissolved in water. ·

Hydrochloric acid (HCl) and   Sulphuric acid (H2SO4)  are strong acids.

 natural acids such as formic acid(HCOOH) and acetic acid (CH3COOH) are weak acids.

-> What will happen when base is dissolved in water?

It will produce hydroxide  ions .

->How you can identify if a substance is acid or base as it is hazardous to taste all chemicals?

By use of indicators.

Type of Indicator		Example
Natural indicator	Naturally occurring substances which act as indicators	Litmus, turmeric, red cabbage and china rose   .
Synthetic indicators	They are produced in the laboratory using chemicals	Phenolphthalein, methyl orange colour indicators
Olfactory indicators		Garlic

                                                                                                

Litmus: ® is one of the earliest known indicators and it is a natural dye obtained from lichens

              ® solution turns red when added to acid solution.

             ® solution turns blue when added to basic solution.

->  When acids dissolves in water which ions are formed.

       Hydrogen  ions

->  Give one example of strong base?

       Sodium hydroxide/ potassium hydroxide/ calcium hydroxide.

->What happens when red litmus paper is dissolved in base?

        Red litmus paper turns blue.

->What are indicators?

         Indicators are substances that changes their properties according to acidic or basic environment.

-> Give examples of natural indicators.

      litmus, china rose, turmeric

 -> What happens when you try to wash a turmeric stain on your clothes with soap?

    The stain turns red in colour.

-> When turmeric paper strip is dipped in the shampoo solution , the  colour  of turmeric paper strip changes to red,

   It indicates that shampoo solution is basic in nature.

 -> When turmeric paper strip is dipped in the cold drink , the colour of turmeric paper strip does not chang.

   Cold drink is acidic in nature.

-> Give any two examples of natural indicators.

Litmus/Turmeric/China rose

 -> Name one synthetic indicator?

Phenolphthalein is a colourless synthetic indicator. When it is added to

 an acidic solution, it remains colourless

 a basic solution ,it turns bright pink.

-> What is the colour obtained when universal indicator is added to hydrochloric acid?

Bright red

->What is the colour obtained when universal indicator is added to calcium hydroxide?

Violet

-> What is the neutralisation reaction?

->When an acid is mixed with base in a suitable quantity, the resulting solution is neither acidic nor basic is known as neutralization  reaction.

->What are the products formed in neutralisation reaction?

Salt and water

->What is the common name of sodium chloride?

     Common salt

->Where do we use sodium chloride in our daily life?

    It is used in food to add taste and it is also used as preservative.

-> What happen when you eat spicy or oily food?  

 we get acidity/heartburn

 -> What you do when you suffer from acidity?

Take medicine to feel better

-> What does this medicine do to control acidity?

It  neutralizes the excess of acid in our stomach.

-> Which acid is present in ant’s bite?

Formic acid

-> What should be added to treat a soil if it’s too basic in nature?

Compost or organic manure should be added to treat the soil if it’s too basic in nature.