Acids, Bases and Salts, Science, Chapter 2, Part-17, Class 10, NCERT solutions

Acids, Bases and Salts

Page Number of the Textbook -17

1. If someone, in the family is suffering from a problem of acidity, after overeating, which of the following would you suggest as a remedy?

(a) lemon juice          (b) vinegar

(c) baking soda solution (d) salt solution

Ans. (c) baking soda solution

2. Fill in the blanks.

(a) Sour and bitter tastes of food are due to ______ and _______ respectively, present in them.

Ans. acids; bases

(b) Acids and bases _______ each other's effect.

Ans. nullify

(c) Acids taste _______.

Ans. sour

(d) Acids turn the colour of  ______ litmus ______.

Ans. blue; red

(e) Bases taste _______.

Ans. bitter

(f) Bases turn  the colour of  ______ litmus ______.

Ans. red; blue

(g ) Litmus is a natural _______.

Ans. indicator

(h) Blue litmus and turmeric are ________ indicator.

Ans. natural

(i) Soap is ______ in nature.

Ans. basic

(j) _____ and ______ examples opf artificial or synthetic indicators.

Ans. methyl orange; phenolphthalein

3. What will be the colour of a litmus paper in an acidic medium?

Ans. Red

4. Give two examples of synthetic indicators.

Ans. Two examples of synthetic indicators are - methyl orange and phenolphthalein.

5. What is the normal colour of a litmus solution?

Ans. purple.

5. What is litmus solution? Write one of its properties.

Ans. Litmus solution is a purple dye, which is extracted from lichen, a plant belonging to the division Thallophyta, and is commonly used as an acid-base indicator.

One of its properties is that in an acidic medium, the colour of a blue litmus turns red, while in a basic medium, the colour of a red litmus turns blue.

Memory Trick - 2.1

Keep saying "ABR" 

or "Assam Bengal Railway".

Meaning : A for Acids, B for Blue and R for Red. ABR this way means Acids turn Blue litmus Red. If we know that acids turn blue litmus red, then it will be easier for us to remember - "Bases turn Red litmus Blue."

6. What is acid-base indicator or simply indicator?

Ans. The substances that change colour in acidic, basic or neutral medium are called acid-base indicators or simply indicators.

7. Give some examples of natural indicators.

Or Give two examples of natural indicators.

Ans. Some examples of acid-base indicators are - litmus, red cabbage leaves, turmeric, some flowers such Hydreangea, Petunia, Geranium etc.