Take things which are sour in taste and used as food. Eg. Curd, lemon juice. If you check these substances with blue and red litmus what happens ?

Which of the above substances changed red litmus to blue ?

Which of the above substances changed the blue litmus to red ?

Statement A : The substances which are sour to taste and turns red litmus to blue are acidic in. Statement B:The substances which are soapy to touch and turns blue litmus to red are basic in nature.

Add sugar to lemon juice. What change do you notice in the taste ?

Basic solution converts red litmus into blue litmus. If you add the substance given below reverse happens

Take solutions of some juices of fruits, vegetables, cold drinks and various solutions in beakers test tubes and test them with blue and red litmus papers. List out results in the table, by marking (?) in the relevant column if the colour changes, put (?) if the colour is unchanged.

Answer the following question One substance is slippery to touch and bitter in taste, another substance is sour in taste. If you add both, which substances will form ?

Take vinegar, lemon juice, soapy water, baking soda in different vessels. Pur beetroot pieces in the vessels. Predict what happens. Verify your prediction by observing the changes. After 10 minutes, 30 minutes, 60 minutes record your observations. What do you conclude?

You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

Substance 'A' : It is produced by non metallic oxide. Substance 'B' : It produces OH- ions in aqueous solution. 1) Which substance can turn blue litmus to red ? Why ? 2) How do you prepare substance 'B' ?