NCERT MCQ Solutions for Class 10 Science Chapter 3 Metals and Non-Metals

Mercury is the only metal that exists as a liquid at room temperature. It is used in thermometers and barometers. Its unique liquid state is due to weak interatomic bonding compared to other metals.

Copper is highly conductive and is widely used in electrical wiring and electronics. It allows electrons to flow with minimal resistance making it an ideal choice for conducting electricity in homes and industries.

Ductility is the property that enables metals to be stretched into thin wires without breaking. This characteristic is important in making electrical cables and wiring materials from metals like copper and aluminum.

Oxygen is vital for aerobic respiration in living organisms. It helps in breaking down food molecules to release energy. Oxygen is inhaled into the lungs diffused into the blood and transported to cells.

Copper is an unreactive metal that does not react with water or steam under normal conditions. It does not displace hydrogen from water and is therefore used in plumbing and water storage applications.

When metals like zinc or magnesium react with dilute acids they displace hydrogen ions to release hydrogen gas. This is a standard method for producing hydrogen in laboratories.

Most non-metals do not allow electric current to pass through them due to the absence of free-moving electrons. Exceptions like graphite exist but generally non-metals are used as insulators.

Galvanisation is the process of coating iron objects with zinc to prevent rusting. Zinc acts as a protective barrier and also offers sacrificial protection corroding first instead of the underlying iron.

Sodium is a highly reactive alkali metal. It reacts rapidly with moisture and oxygen in the air generating heat and catching fire. It is stored under kerosene to prevent such reactions.

CO₂ is a non-metallic oxide that dissolves in water to form carbonic acid making the solution acidic. Acidic oxides are typical of non-metals and are used in soft drink carbonation.

Phosphorus is a non-metal that ignites easily in air. It is a key ingredient in matchstick heads where it helps in initiating combustion when rubbed against a rough surface.

Copper reacts slowly with moist air and carbon dioxide to form a greenish layer of basic copper carbonate which is poisonous and should not be ingested.

Potassium is located at the top of the reactivity series. It reacts explosively with water and is more reactive than other commonly known metals like zinc and iron.

Amphoteric oxides such as aluminium oxide react with both acids and bases to form salt and water. This dual behavior distinguishes them from purely acidic or basic oxides.

Chlorine is a disinfectant commonly added to water to kill harmful microorganisms. It reacts with water to form compounds that effectively eliminate bacteria and viruses.

Metal oxides are basic in nature. They react with acids to form salt and water. This property is used in neutralising acidic soils and industrial waste management.

Graphite is an allotrope of carbon and has free electrons that allow it to conduct electricity. Unlike other non-metals it has a layered structure with mobile electrons.

Gold is a noble metal that is ductile, malleable and has a shiny appearance. It does not corrode or tarnish easily which makes it ideal for ornaments and coins.

Aluminium is extracted from bauxite ore using electrolysis. The process requires high electrical energy and occurs in molten cryolite to lower the melting point and improve conductivity.

Certain metals like aluminium and zinc react with strong bases such as sodium hydroxide to produce hydrogen gas. This reaction also forms complex metal salts in the solution.