1. Fill in the blanks with the appropriate term.
(Temperature, volume, mass, density,
humidity, acidic, weight, neutral, shape.)
(a) The capacity of air to hold moisture depends upon the ……… of the air.
Answer. The capacity of air to hold moisture depends upon the temperature of the air.
(b) Water does not have a ………….but has definite ………. and ………. .
Answer. Water does not have a shape but has definite mass and volume.
(c) While freezing, the ……………….. of water is lowered.
Answer. While freezing, the density of water is lowered.
(d) …………….. soil has pH 7.
Answer. Neutral soil has a pH of 7.
2. Why is it said that –
(a) Air is a homogeneous mixture of various gases.
Answer. Air appears uniform because its components (nitrogen, oxygen, CO₂, etc.) are evenly distributed at the molecular level, with no visible boundaries.
(b) Water is a universal solvent.
Answer. Water dissolves more substances (e.g., salts, sugars) than any other liquid due to its polar nature, which breaks ionic bonds effectively.
(c) There is no alternative to water for cleaning purposes.
Answer. Water’s ability to dissolve dirt, grease, and stains—combined with its safe, abundant, and non-toxic nature—makes it irreplaceable for cleaning.
3. What will happen if…..
(a) The amount of water vapour in the air increases.
Answer. Leads to higher humidity, reduced oxygen efficiency for breathing, and potential condensation (clouds/rain).
(b) Only one crop is grown repeatedly in the soil.
Answer. Repeated single-crop farming:
Depletes soil nutrients (like nitrogen), increases pests, and reduces fertility, causing soil degradation.
4. With whom should I pair up ?
Group ‘A’ Group ‘B’
| Group A | Group B |
| (1) Air | (a) Excretion |
| (2) Water | (b) Scattering of light |
| (3) Soil | (c) Plasticity |
Answer.
| Group A | Group B |
| (1) Air | (b) Scattering of light |
| (2) Water | (a) Excretion |
| (3) Soil | (c) Plasticity |
5. State whether the following statements
are true or false.
(a) Sandy soil has low capacity for holding water.
Answer. True
(b) The substance in which a solute dissolves is called a solvent.
Answer. True
(c) The pressure exerted by air is called atmospheric pressure.
Answer. True