Question

Read the passage given below:-
In biology class, teacher performed an experiment. he took 1 ml of 1% starch solution in one test
tube and 1 ML of 1 % sucrose solution and added 2 ML of Benedict’s solution in each of the tube
and boiled for a couple of minutes. No changes occurred in either of the tubes.
Next he collected 2 ML of saliva in each of the two fresh tubes and added 1 ML of 1 % starch solution
to one of the them 1 ML of 1 % sucrose solution to other and kept for half an hour at room
temperature. Then added 2ML of Benedict’s solution to both test tubes and boiled each of the tube
for a couple of minutes. The blue colour of the benedicts solution changes to yellow or red in the
test tube containing starch.

(i) Why did blue colour not changed in the two tubes initially?

(ii) Why did blue colour change to yellow or red in the tube containing starch and saliva?

(iii) Why the sucrose solution with saliva did not showed any change?

(iv) Importance of saliva.​

Answer 1

Answer:

Blue is a very prominent colour on earth. But when it comes to nature, blue is very rare. ... Pigments appear the colour of the light they don't absorb, but instead reflect. The most common plant pigment is green chlorophyll, so plants appear green because chlorophyll doesn't absorb, but rather reflects, green light.Aug