MCQs ON PRACTICAL SKILLS- CLASS IX BIOLOGY

EXPERIMENT NO.3

AIM: To test (a) The presence of starch in food (b) presence of metanil yellow in dal.

1. Which reagent gives blue colour with starch?

a. safranin

b. methylene blue

c. iodine

d. eosin

2. starch solution gives blue colour with iodine solution. What will happen if the blue colour starch solution is boiled?

a. blue colour disappears

b. no change

c. a brick red colour appears

d. blue colour becomes dark

3. Which food sample you will select to test the presence of starch?

a. grape

b. coconut

c. gram seed

d. potato

4.Which of the following gives blue colour with iodine?

a. sago powder

b. powdered sugar

c. common salt

d. chalk powder

5. What colour appears if HCl is added to adulterated arhar dal with metanil yellow?

a. Yellow

b. pink

c. blue

d. red

6. X washed small amount of arhar dal in small amount of water. The water became yellow. He put a few drops of HCl in a test tube containing yellow water. The sample turned pink. This shows that

a. dal is not adulterated

b. dal contains protein

c. dal is adulterated with metanil yellow

d. dal is coloured with turmeric

7. Iodine gives blue-black colour with

a. protein

b. oil

c. starch

d. sucrose

8. The colour of arhar dal which is adulterated with metanil yellow, is

a. plain yellow

b. sunshine yellow

c. chrome yellow

d. brilliant yellow

9. Adulterant arhar dal is plain yellow in colour due to

a. turmeric

b. sulphur powder

c. metanil yellow

d. chrome yellow

10. when iodine is added to starch solution, following colour appears

a. brick red

b. magenta

c. blue-black

d. green

11. Metanil yellow, an adulterant used in arhar dal is basically

a. an acid

b. a detergent

c. a dye

d. none of the above

12 Following are the 4 operations for testing presence of starch in rice (i) put few rice grains in a test tube (ii) add few drops of iodine solution (iii) add water in the test tube (iv) boil the test tube and filter the content. The correct sequence is

a. i ii iii iv

b. i iii iv ii

c. i ii iv iii

d. i iii ii iv

13 Given below are 4 operations for testing metanil yellow in arhar dal. (i) make powder of 5g of dal and put it in a test tube. (ii) add 2-4 drops of conc. HCl. (iii) Filter the content and keep the filtrate separately. (iv) add 10 ml of water and shake well. The correct sequence is

a. i iii ii iv

b. i iv iii ii

c. i ii iii iv

d i ii iv iii

14. X was rushing with a bottle of iodine solution. Some iodine solution splashed on his yellow coloured cotton shirt and also on the white table cloth. The stain on the table cloth was yellowish brown while that on his shirt was blue black. The most plausible scientific reason for this is that the

a. shirt was dyed with metanil yellow

b. shirt was starched after washing

c. table cloth was starched but not shirt

d. shirt had absorbed sweat

Answers:-