MEDIUM
9th CBSE
IMPORTANT
Earn 100

Under which category of mixtures will you classify alloys and why?

Important Questions on Is Matter Around Us Pure?

MEDIUM
9th CBSE
IMPORTANT
A solution is always a liquid. Comment.
MEDIUM
9th CBSE
IMPORTANT
Can a solution be heterogeneous?
HARD
9th CBSE
IMPORTANT
Iron filings and sulphur were mixed together and divided into two parts, A' and 'B.  Part 'A' was heated strongly while Part 'B' was not heated. Dilute hydrochloric acid was added to both the parts and evolution of gas was seen in both the cases. How will you identify the gases evolved?
HARD
9th CBSE
IMPORTANT

A child wanted to separate the mixture of dyes constituting a sample of ink. He marked a line by the ink on the filter paper and placed the filter paper in a glass containing water as shown in the image. The filter paper was removed when the water moved near the top of the filter paper.

Question Image  

(i) What would you expect to see, if the ink contains three different coloured components?

(ii) Name the technique used by the child.

(iii) Suggest one more application of this technique.

HARD
9th CBSE
IMPORTANT

A child wanted to separate the mixture of dyes constituting a sample of ink. He marked a line by the ink on the filter paper and placed the filter paper in a glass containing water as shown in Fig. The filter paper was removed when the water moved near the top of the filter paper.

Question Image

Name the technique used by the child.

HARD
9th CBSE
IMPORTANT

A child wanted to separate the mixture of dyes constituting a sample of ink. He marked a line by the ink on the filter paper and placed the filter paper in a glass containing water as shown in Fig. The filter paper was removed when the water moved near the top of the filter paper.

Question Image

Suggest one more application of this technique.

HARD
9th CBSE
IMPORTANT

A group of students took an old shoe box and covered it with a black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box as shown in the figure. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it?

Question Image

(a) Explain why the milk sample was illuminated. Name the phenomenon involved.

(b) Same results were not observed with a salt solution. Explain.

(c) Can you suggest two more solutions which would show the same effect as shown by the milk solution?

MEDIUM
9th CBSE
IMPORTANT

A group of students took an old shoebox and covered it with a black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box as shown in the
Fig. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it?

Question Image

Same results were not observed with a salt solution. Explain.