Table of Contents
Ans. (d)
Explanation:
Non-metals are generally not lustrous, meaning they do not have a shiny appearance. However, iodine is an exception. Iodine is a non-metal that has a lustrous (shiny) appearance when in its solid form. It exhibits a metallic-like sheen, unlike other non-metals like sulphur, oxygen, and nitrogen, which are dull in appearance.
Ans. (c)
Explanation:
Amphoteric oxides are oxides that can react with both acids and bases to form salts and water. Aluminium oxide (Al₂O₃) is an example of an amphoteric oxide. It reacts with both acids and bases, unlike the oxides of metals like sodium (Na), calcium (Ca), and copper (Cu), which are basic in nature and react with acids only.
Explanation:
When most metals (except manganese and magnesium) react with nitric acid (HNO₃), hydrogen gas is not liberated because nitric acid is a strong oxidising agent. Instead of releasing hydrogen gas, it oxidises the hydrogen into water (H₂O). As a result, nitric acid itself is reduced, producing nitrogen oxides such as NO₂ or NO depending on the concentration of the acid.
However, manganese (Mn) and magnesium (Mg) are exceptions, as they are highly reactive metals and can displace hydrogen even from nitric acid.
Explanation:
Copper is used for making electric wires because it has excellent electrical conductivity, allowing electric current to flow through with minimal resistance. Additionally, copper is highly ductile, meaning it can be easily drawn into thin wires without breaking, which is essential for wiring. While other metals like silver have better conductivity, copper offers the best balance between cost and efficiency, making it the most practical choice for electrical wiring.
Explanation:
Metals are a category of elements characterised by their ability to conduct heat and electricity, malleability (ability to be hammered or rolled into thin sheets), ductility (ability to be drawn into wires), and typically a shiny appearance. They often form positive ions by losing electrons and are usually solid at room temperature (with the exception of mercury). The five metals are: Iron, aluminium, copper gold and silver.
| Chapter No. | Chapter Name |
|---|---|
| Chapter 1 | Chemical Reactions and Equations |
| Chapter 2 | Acid, Bases and Salts |
| Chapter 3 | Metals and Non-Metals |
| Chapter 4 | Carbon and its Compounds |
| Chapter 5 | Life Processes |
| Chapter 6 | Control and Coordination |
| Chapter 7 | How do Organisms Reproduce |
| Chapter 8 | Heredity |
| Chapter 9 | Light : Reflection and Refraction |
| Chapter 10 | The Human Eye and the Colourful world |
| Chapter 11 | Electricity |
| Chapter 12 | Magnetic Effects of Electric Current |
| Chapter 13 | Our Environment |
| Chapter Wise Important Questions for CBSE Board Class 10 Science |
|---|
| Chemical Reactions and Equations |
| Acid, Bases and Salts |
| Metals and Non-Metals |
| Carbon and its Compounds |
| Life Processes |
| Control and Coordination |
| How do Organisms Reproduce |
| Heredity |
| Light : Reflection and Refraction |
| The Human Eye and the Colourful world |
| Electricity |
| Magnetic Effects of Electric Current |
| Our Environment |
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