State with reason(s) whether the following statements are True [T] or False [F].
Aluminium and copper are examples of non-metals used for making utensils and statues.
False. Aluminium and copper are metals, not non-metals. They are used for making utensils and statues because metals are generally malleable, ductile, good conductors of heat, and lustrous in appearance.
Metals form oxides when combined with oxygen, the solution of which turns blue litmus paper to red.
False. Metal oxides are basic in nature. When metal oxides dissolve in water, they form basic solutions which turn red litmus paper to blue, not blue litmus to red.
Oxygen is a non-metal essential for respiration.
True. Oxygen is a non-metal that is essential for all living organisms. We breathe in oxygen for respiration, and without it, we would not be able to survive.
Copper vessels are used for boiling water because they are good conductors of electricity.
False. Copper vessels are used for boiling water because copper is a good conductor of heat, not electricity. Good heat conduction allows efficient transfer of heat from the flame to the water for cooking.
Explanation
(i) The chapter clearly identifies aluminium and copper as metals. The chapter states that metals like copper, aluminium, and iron are lustrous, hard, malleable, and ductile. Non-metals like sulfur and phosphorus are soft, dull, and neither malleable nor ductile. (ii) The chapter explains through Activity 4.6 that when magnesium (a metal) burns in oxygen, it forms magnesium oxide, which when dissolved in water forms a basic solution. This basic solution changes red litmus to blue. Acidic solutions turn blue litmus to red, but metal oxides are basic. (iii) The chapter explicitly states in section 4.5 that oxygen is a non-metal essential for respiration and that without it, we would not be able to survive. (iv) The chapter explains in section 4.1.4 that metals are good conductors of heat, which is why they are used for making cooking vessels. While copper is also a good conductor of electricity, the primary reason for using copper vessels for cooking is its excellent heat conduction property.