Question

3. Turmeric is a natural indicator. On
adding acid and base separately to its
paste, what would happen?
(a) Yellow in both acid and base.
(b) Yellow in acid and red in base.
(c) Pink in acid and yellow in base.
(d) Red in acid and blue in base.
4. Phenolphthalein is a synthetic
indicator and its colours in acidic and
basic solutions, respectively are
(a) red and blue.
(b) blue and red.
(c) pink and colourless.
(d) colourless and pink
5. When the soil is too basic, plants do
not grow well in it. To improve its quality
what must be added to the soil?
(a) Organic matter
(b) Quick lime
(c) Slaked lime
(d) Calamine solution​

Answer 1

Answer:

3 rd one answer - b , 4d one answer - d , 5th - organic matter

Explanation:

3 rd - Turmeric is yellow in acidic and neutral solutions; is bright red in basic solutionst ,

4d - Phenolphthalein [3,3-Bis (4- hydroxyphenyl)- 2 benzofuran- 1-one] is often used as an indicator in acid-base titrations. It turns colourless in acidic solutions and pink in basic solutions.

5th - To improve the quality of a basic soil, an acid should be added. Slaked lime (Ca(OH)2) and quick lime (CaO) are basic in nature. Urea is neutral. Hence, organic matter is the answer.