Class 10 CBSE Science chapter 3 Metals And Non Metals Activities solutions | All activities Solutions NCERT Science chapter 3

 

Metals and Non-metals Class 10 All Activities Solutions Chapter 3

All the solutions of activities NCERT Class 10 chapter 3 with PDF.

These activities are very important in exam point of view . CBSE often asks questions from these . 

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ACTIVITY 3.1

Here’s a description of the appearance of each metal sample, both before and after cleaning with sandpaper:

1. Iron

• Before Cleaning: Appears dull grey or black and may reddish-brown if it has been exposed to moisture.

• After Cleaning: shiny and silver-grey.

2. Copper

• Before Cleaning: reddish-brown colour and can develop a green patina over time if exposed to air and moisture.

• After Cleaning: shines with a bright, metallic reddish-orange appearance.

3. Aluminium

• Before Cleaning: silvery-grey colour but may appear dull due to the natural oxide layer on its surface.

• After Cleaning: a shiny, reflective surface that is bright and silver in colour.

4. Magnesium

• Before Cleaning: dull greyish-white colour.

• After Cleaning: exhibits a brighter, more metallic finish, showing a lighter silver-grey colour.

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ACTIVITY 3.2

Iron, Copper, Aluminium, and Magnesium:

• Iron: Iron is tough and does not easily cut.
• Copper: Copper is relatively soft and can be cut
• Aluminium: Aluminium is also relatively soft and can be cut fairly easily
• Magnesium: it can be cut easily with a knife, producing a fine, shiny edge.

Sodium Metal: It can be cut easily with a knife, yielding a shiny, fresh surface.

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ACTIVITY 3.3

 

·        Iron: When struck, iron shows minor dents and retains its overall shape. It’s hard but can deform if struck repeatedly.

·        Zinc: Zinc is much softer than iron. It deforms easily and shows significant dents.

·        Lead: Lead is very soft. When struck, it changes shape a lot making deep dents with little effort. It changes shape easily.

·        Copper. Striking it results in noticeable dents and some deformation. It changes shape also .

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ACTIVITY 3.4

Copper , Aluminium , Nickel , Iron

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ACTIVITY 3.5

Observation of the Pin: The pin at the free end will fall off. This happens because the wax holding the pin melts due to transfer of heat. Generally, the metal wire itself will not melt under normal heating conditions with a candle or spirit lamp as these sources do not produce enough heat to reach the melting points of these metals.

This shows that while the wire conducts heat, it remains solid during the process.

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ACTIVITY 3.6

When you set up the electric circuit and place the metal between terminals A and B, if the bulb glows, it indicates that the metal is a good conductor of electricity. Conversely, if the bulb does not glow, it suggests that the metal is either a poor conductor or an insulator . Thus, the bulb's behaviour helps to determine the electrical conductivity of the metal .

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ACTIVITY 3.7

 On doing activities from 3.1 to 3.4 and 3.6 the followings are the observations :

Activity 3.1: Appearance

• Carbon (Graphite): Black and shiny; coal is dull.
• Sulfur: Bright yellow and brittle.
• Iodine: Dark grey or purple crystals.

Activity 3.2: Cutting

• Carbon (Graphite): Soft and easy to cut.
• Sulfur: Brittle; breaks easily.
• Iodine: Brittle; shatters when cut.

Activity 3.3: Striking

• Carbon: Graphite may deform; coal may break.
• Sulfur: Cracks or shatters.
• Iodine: Breaks into smaller pieces.

Activity 3.4: Common wires :

• Non-metals like carbon, sulphur and iodine are not used in wire form.

Activity 3.6: Electric Circuit

• Carbon (Graphite): May conduct electricity and cause the bulb to glow.
• Sulfur: Does not conduct electricity
• Iodine: Does not conduct electricity

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ACTIVITY 3.8

1. Burning Magnesium:
• Observation: When you burn the magnesium ribbon, it produces a bright white flame, and magnesium oxide (MgO) is formed as a white ash. On dissolving it in water and on dipping litmus paper to it :
• Red Litmus: turns blue
• Blue Litmus: no color change
• Conclusion: The solution is basic due to the formation of magnesium hydroxide Mg(OH)₂.

Reaction Equation:    2Mg(s) + O₂(g) → 2MgO(s)

                                  MgO(s) + H₂O(l) → Mg(OH)₂ (aq)

2. Burning Sulphur:
• Observation: When you burn sulphur powder, it produces a blue flame and emits sulphur dioxide (SO₂) gas.
• Collecting Fumes: Place a test tube over the burning sulphur to capture the fumes.

On doing litmus test after dissolving in water :

• Litmus Test:
• Red Litmus: No change (remains red).
• Blue Litmus: Turns red.
• Conclusion: The solution is acidic due to the formation of sulphurous acid (H₂SO₃).

Reaction Equation: S(s)+O₂​(g)→SO₂​(g)

                             SO₂​(g)+H_2​O(l)→H_2​SO₃​(l)

 

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ACTIVITY 3.9

• Magnesium metal burns easily .
•  It burns with white dazzling flame .
• The metal turns into an white ash i.e Magnesium hydroxide
• Therefore, Reactivity Order (decreasing) towards oxygen is Na,Mg,Al,Zn,Fe,Pb,Cu
•  CuO, Fe₂O₃, PbO, Al₂O₃, etc. are insoluble in water

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ACTIVITY 3.10

• Only Sodium , Potassium and Calcium reacts with cold water .Reactivity series with respect to water is Ca<Na<K
• Yes Potassium and Sodium caught fire .
• Yes Calcium start floating after sometimes because of bubbles of hydrogen gas .
•  Metals such as lead, copper, silver and gold do not react even with steam .
• Metals in the decreasing order of reactivity with water are K>Na>Ca>Mg

 

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ACTIVITY 3.11   

·        Magnesium reacted vigorously with dilute hydrochloric acid .

·        In the case of Magnesium the temperature was recorded highest .

·        The metals in the decreasing order of reactivity towards dilute acids are K>Na>Ca>Mg>Al>Zn>Fe

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ACTIVITY 3.12

1.      A reaction has occurred in the test tube with the iron nail and copper sulphate solution.

2.      Basis for Reaction: The change in colour of the copper sulphate solution and the deposition of copper on the iron nail indicates that iron has displaced copper from the solution.

3.      In conclusion of Activities 3.9 and 3.10 copper was least reactive. Here, the displacement reaction shows that iron is more reactive than copper .

4.      Balanced Chemical Equation:

Fe(s)+CuSO₄(aq)→FeSO₄(aq)+Cu(s)

Type of Reaction: Displacement reaction

 

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ACTIVITY 3.13

1. Physical State of Salts: All the three salts are solid .

2.      Observations After Heating:

• Sodium Chloride: Does not impart colour to the flame; does not melt .
• Potassium Iodide: Imparts a lilac or light purple colour to the flame; does not melt.
• Barium Chloride: Imparts a green colour to the flame; does not melt.

3.      Solubility Tests:

• Dissolving in Water: All these salts are soluble in water .
• Dissolving in Petrol and Kerosene: All three salts (NaCl, KI, BaCl₂) are insoluble .

4.      Electrical Conductivity Test: All Salts (NaCl, KI, BaCl₂): When dissolved in water, the solutions conduct electricity, which indicates that they dissociate into ions.

5.      Conclusions and Inferences: These compounds are ionic salts. These salts dissociate into ions (e.g., Na⁺, Cl⁻, K⁺, I⁻, Ba²⁺) when dissolved in water and conduct electricity . Their flame colours helps to identify the metal ions present. None of the salts melted , this is the general characteristic of ionic salts .

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ACTIVITY 3.14

Observations :

• Test Tube A: Nail rusts due to the presence of water and air.
• Test Tube B: Nail remains unaffected because the oil prevents air contact.
• Test Tube C: Nail remains unaffected as calcium chloride absorbs the moisture.

Conclusion

Rusting can only occur in the presence of water and oxygen . ___________________________________________________________________________________

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