Question 1

Q1: Which metal is commonly used to make food packaging materials as it is cheaper, and its thin sheets can be folded easily into any shape? (i) Aluminium...

Accepted Answer

The correct answer is (i) Aluminium. Aluminium is used for food packaging because it is cheaper, malleable, and can be easily folded into any shape.

Question 2

Q10: One of the methods of protecting iron from getting rusted is to put a thin coating of zinc metal over it. Since sulfur does not react with water, can...

Accepted Answer

No, sulfur cannot be used to protect iron from rusting, even though it does not react with water. The primary reason a coating of zinc (galvanization) protects iron is that zinc corrodes preferentially. Zinc reacts with air and moisture to form a protective layer of zinc oxide and zinc carbonate. Th...

Question 3

Q2: Which of the following metal catches fire when it comes in contact with water? (i) Copper (ii) Aluminium (iii) Zinc (iv) Sodium

Accepted Answer

The correct answer is (iv) Sodium. Sodium reacts vigorously with water, generating heat and catching fire.

Question 4

Q3: State with reason(s) whether the following statements are True [T] or False [F]. (i) Aluminium and copper are examples of non-metals used for making u...

Accepted Answer

(i) False [F]. Aluminium and copper are metals. (ii) False [F]. Metal oxides are generally basic in nature, so their solutions turn red litmus paper blue. (iii) True [T]. Oxygen is a non-metal required for respiration. (iv) True [T]. Copper is a good conductor of heat, making it suitable for boiling...

Question 5

Q4: Why are only a few metals suitable for making jewellery?

Accepted Answer

Only a few metals are suitable for making jewellery because of their properties such as lustre, malleability, ductility, resistance to corrosion, and rarity. Metals like gold, silver, and platinum possess these desirable properties, making them ideal for jewellery making. Their lustrous appearance a...

Question 6

Q5: Match the uses of metals and non-metals given in Column I with the jumbled names of metals and non-metals given in Column II. Column I Column II (i) U...

Accepted Answer

(i) Used in electrical wiring - (c) PEPORC (COPPER) (ii) Most malleable and ductile - (e) O G D L (GOLD) (iii) Living organisms cannot survive without it - (a) E N X Y G O (OXYGEN) (iv) Plants grow healthy when fertilisers containing it are added to the soil - (d) TENGOINR (NITROGEN) (v) Used in wat...

Question 7

Q6: What happens when oxygen reacts with magnesium and sulfur. What are the main differences in the nature of products formed?

Accepted Answer

When oxygen reacts with magnesium, magnesium oxide is formed: $2Mg + O_2 \rightarrow 2MgO$. Magnesium oxide is basic in nature. It turns red litmus paper blue. When oxygen reacts with sulfur, sulfur dioxide is formed: $S + O_2 \rightarrow SO_2$. When sulfur dioxide is dissolved in water, sulfurous a...

Question 8

Q7: 8. You are provided with the following materials. Discuss which material would be your choice to make a pan that is most suitable for boiling water an...

Accepted Answer

A pan made of copper would be most suitable for boiling water. Copper is a good conductor of heat, which means it transfers heat quickly and efficiently. This allows the water to heat up faster and boil more quickly. Iron is also a good conductor of heat, but copper is generally better. Sulfur, coal...

Question 9

Q8: You are provided with three iron nails, each dipped in oil, water and vinegar. Which iron nail will not rust, and why?

Accepted Answer

The iron nail dipped in oil will not rust. Rusting requires both air and water. The oil forms a protective layer around the iron nail, preventing it from coming into contact with both air and water. The nail in water will rust because it is exposed to both air and water. The nail in vinegar will rus...

Question 10

Q9: How do the different properties of metals and non-metals determine their uses in everyday life?

Accepted Answer

The different properties of metals and non-metals determine their uses in everyday life. Metals are strong, malleable, ductile, and good conductors of heat and electricity. These properties make them suitable for making utensils, wires, machinery, and structural components. Non-metals, on the other...

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