Question

Four students called A, B, C and D conducted an experiment to study the properties of different solutions. They took test tubes half filled with water and added sugar, milk, chalk powder and starch powder respectively in to the test tubes labelled as P, Q, R, S and stirred them throughly. Now choose the correct observation from the following​

Answer 1

Answer:

2 I guess.. because I read it in class 9

Answer 2

The correct observation is (3).

Explanation:

Let us first identify the type of mixture produced after the addition of substances:

TEST TUBE                    SOLUTE                      RESULTING MIXTURE

      A                               Sugar                                  True Solution

      B                                 Milk                                         Colloid

      C                           Chalk Powder                         Suspension

      D                           Starch Powder                            Colloid

The following are the properties of a true solution:

• homogeneous,
• particles do not settle,
• do not show the Tyndall effect, and
• no sedimentation

⇒ Observation (1) is incorrect as a true solution does not show the Tyndall effect.

⇒ Observation (4)  is incorrect as a true solution does not show sedimentation.

The following are the properties of a suspension:

• heterogeneous,
• particles settle down,
• do not show the Tyndall effect, and
• sedimentation of particles

⇒Observation (2) is incorrect as a suspension is not homogeneous.

So, the only correct observation is (3).