What name is given to those substances which do not change the colour of either red or blue litmus paper?

2

(a)

Write the name of two indicators which occur naturally.

2

(a)

Name the acid present in lemon juice and tomato.

2

(a)

Name a substance which is used to cure the discomfort caused by indigestion due to over eating.

2

(a)

Why does a turmeric stain on white shirt is turned to red when it is washed with soap?

2

(a)

Name one acid which is responsible for acid rain.

2

(a)

Form a sentence using the following words: baking soda, ant bite, moist, effect, neutralised, rubbing.

2

(a)

Which part of our body contains hydrochloric acid?

2

(a)

Why does a vegetable stain turns reddish brown when washed with soap?

2

(a)

Which indicator is generally used to observe neutralization reaction?

2

(a)

What is litmus? How is it prepared?

2

(a)

Take tap water, vinegar and washing soda solution. Put a drop of these solutions on the red litmus and blue litmus paper and write their observation.

2

(a)

How do you prepare turmeric paper?

2

(a)

Why do copper and brass vessels need kalai?

2

(a)

Brushing our teeth twice a day is well known saying. Justify this statement.

2

(a)