Chapter 3 – Metals and Non-metals

1) Do ionic compounds possess higher melting points?

Ans – Ionic compounds possess higher melting points primarily due to the robust electrostatic forces of attraction among the opposite ions (cations & anions) that make up their crystal lattice structures.

Ionic compounds create a crystalline lattice feature where oppositely charged ions surround each ion in a repeating & stable pattern. This structure maximizes the attractive forces over ions by contributing to stability and solid strength.

2) What’s meant by amphoteric oxides? Explain with examples.

Ans – Amphoteric oxides are oxides that can react both as acids and bases. This dual behavior allows them to merge with acids and bases to form salts and water. Amphoteric oxides often contain elements that are metalloids or transition metals.

For example, Aluminum oxide (AI₂O₃) and Zinc Oxide (ZnO)

3) How is Galvanization a solution to the rusting of iron?

Ans – Galvanization is a process used to protect iron from rusting by coating it with a layer of zinc. This method effectively checks to rust through a physical barrier and electrochemical protection, that prevents moisture, oxygen, and other corrosive substances from reaching the underlying metal.

Zinc is more reactive (more anodic) than iron in the electrochemical series. When the galvanized metal is exposed to an environment that causes rusting (oxidation), the zinc preferentially oxidizes instead of the iron. This sacrificial oxidation of zinc protects the iron beneath it.

4) What do you mean by thermit reaction?

Ans – The thermite reaction, also known as the aluminothermic reaction, is a highly exothermic redox chemical reaction between a metal oxide and aluminum powder. This reaction is typically used for welding and producing high temperatures to reduce or melt metals.

The most common form of this reaction involves iron(III) oxide (rust) and aluminum powder mostly used in railway tracks and machinery.

5) Write the difference between electrolytic and carbon reduction stating one point with examples.

Ans – Regarding electrolytic reduction, electrolysis is the reduction agent, where the cathode gets reduced by gaining electrons.

Example:-

However, when it comes to reduction with carbon, the reducing agent is carbon, where the reduction happens by heating a metal oxide with coke.

Example:-

6) Give 2 ways to prevent iron rusting.

Ans –

• By coating the iron surface with grease, paint, or oil.
• By galvanizing the iron depositing a zinc layer on the iron surface.

7) List the differences between metals and non-metals based on their chemical properties.

Metals	Nonmetals
They react with mineral acids producing salt and some gas.	They typically do not react with mineral acids.
Metals are good reducing agents.	Non-metals are good oxidizing agents.
Metallic oxides are basic.	Non-metallic oxides are acidic.
Metallic hydrides are unstable.	Non-metallic hydrides are stable.
Metals can displace hydrogen from water.	Non-metals do not react with water or steam.

8) Metal X comes in the form of fillings and when sprinkled on flame, burins vigorously. Upon being treated with sulfur, these fillings form a black-colored compound Y, which is not attracted by a magnet. X when added to dilute HCL, produces Hydrogen gas. However, when reacted with steam, it produces Z & Hydrogen gas. What are X, Y, and Z? Answer with balanced equations.

Ans – From the above data, we can say that metal X reacts with steam and HCL and produces hydrogen gas. However, X is magnetic but its sulfide is not. Hence, it can be concluded that X is iron while Y is iron sulfide.

Similarly, when X reacts with steam, it produces Z which is iron (ii, iii) oxide.

Reactions –

Iron filings with sulphur: Fe + S → FeS

Iron filings with hydrochloric acid: Fe + 2HCI → FeCI, +H₂

Iron filings with steam: 3Fe + 4H₂O → Fe₃0₄ + 4H₂

9) Write three common forms of metal as they occur in nature. Explain what happens when metals interact with dilute acid.

Ans – The 3 most common forms of metal in nature are –

• Sulphide form – e.g. copper pyrite (CuFeS₂)
• Oxide form – e.g. Bauxite (AI₂O₃.2H₂O)
• Carbonate form – e.g. Calamine (ZnCO₃)

Active metals react with dilute HCL or dilute H₂SO₄  and produce hydrogen gas. However, the metals below Hydrogen in the electrochemical series do not do so.

Here are some examples –

Fe + 2HCI → FeCI₂ + H₂ ↑

Mg + 2HCI → MgCI₂ + H₂ ↑

10) Four metal samples- A, B, C, and D were taken and introduced to different solutions. Here is the list of gathered results –

Metal	FeSO4	CuSO4	ZnSO4	AgNO3
A	No Reaction	Displacement	—	—
B	Displacement	—	No Reaction	—
C	No Reaction	No Reaction	No Reaction	Displacement
D	No Reaction	No Reaction	No Reaction	No Reaction

From the table, answer the following questions about the metals.

a. Which one among them is the most reactive metal?

Ans – Metal sample B is the most reaction since it displaces iron from the solution, the most reactive metal in the activity series.

b. What happens when the metal sample B is added to copper (II) sulfate solution?

Ans – From the table, it can be said that B is more reactive than iron. Since copper is less reactive than iron, metal B will also displace copper from the copper sulfate solution.

c. Arrange the metal samples in the order of decreasing reactivity. 

Ans- The metals in the order of decreasing reactivity are as follows –

B>A>C>D.