Answer:
Q1. Rain dissolves carbon dioxide from air to form carbonic acid. Other gases produced by industry causes rain to be more acidic. These gases are sulphur dioxide and nitrogen dioxide. When they dissolve in water, they form sulfuric acid and nitric acid. Burning fossil fuels such as coal and oil give off these gases causing acid rain. Acid rain damages plants and buildings. It also pollutes water killing fish.
Q2(b). Phenolphthalein will be:
(i) colorless in acid.
(ii) pink in alkaline.
Q3(a). Colour of pH scale:
1-2 - red
3-6 - orange or yellow
7- green
8-11 - blue
12-14 - violet or indigo
Q3(b).
1-2 - strong acid
3-6 - weak acid
7- neutral
8-11 - weak alkali
11-14 - strong alkali
1a. How acid rain alter pH of soil:
When acid rain falls on soil, it leaches the existing soil nutrients from the soil. This leads to the soil acidification; thereby making soil more acidic. As the pH of the soil becomes more acidic, the number of micro-organisms in the decreases.
1b. Vegetables that prefer acidic conditions:
1. carrots
2. potatoes
1c. Vegetables that tolerate alkaline conditions:
1. Onions
2. beans
1d. Vegetables that can tolerate the widest pH range:
1. onions
2. potatoes
1e. Vegetables that grow in neutral soil:
About 3 vegetables
Explanation:
Further depletion by acid rain leads to reduction in available plant life and micro-organisms.
Phenolphthalein is known to be naturally colorless. This indicator turns pink in alkaline solutions. It actually remains colorless throughout the range of acidic pH levels.
