(i). Tomato juice is likely to be sour in taste because its pH is less than 7. Substances with a pH below 7 are acidic, and acids typically taste sour
(ii). A strong acid ionizes completely in water, releasing a large number of \( \text{H}^+ \) ions.
Example:\[\text{HCl} \rightarrow \text{H}^+ + \text{Cl}^-.\]
A weak base partially ionizes in water, releasing fewer \( \text{OH}^- \) ions.
Example:\[\text{NH}_4\text{OH} \rightleftharpoons \text{NH}_4^+ + \text{OH}^-.\]
(iii). Acid rain lowers the pH of water bodies, making the water acidic. This affects aquatic life because:
• It damages the gills of fish and other aquatic organisms.
• It reduces the availability of essential minerals by dissolving toxic metals like aluminum.
Match Column-I with Column-II and choose the correct option:
| Column-I (Minerals) | Column-II (Features) | ||
|---|---|---|---|
| A. | Copper | (i) | Used in manufacturing of steel and plants |
| B. | Bauxite | (ii) | Used in electric and electronic industries |
| C. | Mica | (iii) | Used in electric cables and utensils |
| D. | Manganese | (iv) | Used in aluminium production |
Choose the correct answer from the options given below:
Give reasons:
(i) The sky appears dark to passengers flying at very high altitudes.
At very high altitudes, passengers are above the atmosphere where there is less scattering of sunlight. As a result, they do not see the scattered blue light and the sky appears dark, similar to the condition experienced by astronauts in space.
(ii) 'Danger' signal lights are red in color.