Q1.
Mixtures could be of several types depending on the physical state of their components. Some mixtures with their examples are shown in Table 8.1. Complete the third column—
| S.No. | Mixture-type | Examples | Uniform or non-uniform |
|---|---|---|---|
| 1. | Gas and gas | Air | Uniform |
| 2. | Gas and liquid | Aerated water (soda water) Oxygen dissolved in water | …………………… …………………… |
| 3. | Solid and gas | Carbon particles in air | …………………… |
| 4. | Liquid and liquid | Acetic acid in water (vinegar) Oil and water | …………………… …………………… |
| 5. | Solid and liquid | Sand and water Seawater | …………………… …………………… |
| 6. | Solid and solid | Baking powder (baking soda and tartaric acid) Alloys | …………………… …………………… |
Answer
The column to be filled is the one headed Uniform or non-uniform. Judge each example by one test: can the components be seen separately?
| S.No. | Mixture-type | Examples | Uniform or non-uniform |
|---|---|---|---|
| 1. | Gas and gas | Air | Uniform |
| 2. | Gas and liquid | Aerated water (soda water) Oxygen dissolved in water | Uniform Uniform |
| 3. | Solid and gas | Carbon particles in air | Non-uniform |
| 4. | Liquid and liquid | Acetic acid in water (vinegar) Oil and water | Uniform Non-uniform |
| 5. | Solid and liquid | Sand and water Seawater | Non-uniform Uniform |
| 6. | Solid and solid | Baking powder (baking soda and tartaric acid) Alloys | Non-uniform Uniform |
Why these answers: Soda water, dissolved oxygen, vinegar and seawater are all cases where one substance has dissolved fully in the other, so the mixture is the same everywhere — uniform. Carbon particles in air, oil on water and sand in water stay as separate specks, layers or grains you can see, so they are non-uniform. Baking powder is a mechanical mixture of two white powders — under a magnifying glass the two kinds of grains can be told apart. Alloys are the special case: metals melted together mix so evenly that even a microscope shows one substance throughout.
Tip: The English book says "Complete the third column" while the blank column in Table 8.1 is actually the fourth; the Hindi edition of the same page correctly says चौथा स्तंभ (fourth column). Fill the Uniform or non-uniform column.