Name the ore of mercury and state the form in which it is found in nature. Write the chemical equations along with the condition required for the reactions involved in the extraction of mercury from its ore.

Q: Name the ore of mercury and state the form in which it is found in nature. Write the chemical equations along with the condition required for the reactions involved in the extraction of mercury from its ore.

1. **Ore of Mercury**: Cinnabar. 2. **Form in Nature**: It is found in the form of a sulphide ore, chemically known as Mercury(II) sulphide ($ \text{HgS} $). 3. **Chemical Equations and Conditions for Extraction**: - **Step 1 (Roasting)**: Cinnabar is heated strongly in the presence of excess air (oxygen) to convert it into mercury(II) oxide ($ \text{HgO} $). $$2\text{HgS(s)} + 3\text{O}_2\text{(g)} \xrightarrow{\text{Heat}} 2\text{HgO(s)} + 2\text{SO}_2\text{(g)}$$ - **Step 2 (Reduction)**: The mercury(II) oxide is then reduced to mercury metal upon further heating. $$2\text{HgO(s)} \xrightarrow{\text{Heat}} 2\text{Hg(l)} + \text{O}_2\text{(g)}$$

Metals and Non-metals

Extraction of Metals

Official Answer

Ore of Mercury: Cinnabar.
Form in Nature: It is found in the form of a sulphide ore, chemically known as Mercury(II) sulphide ( $\text{HgS}$ ).
Chemical Equations and Conditions for Extraction:

Step 1 (Roasting): Cinnabar is heated strongly in the presence of excess air (oxygen) to convert it into mercury(II) oxide ( $\text{HgO}$ ).

$2\text{HgS(s)} + 3\text{O}_2\text{(g)} \xrightarrow{\text{Heat}} 2\text{HgO(s)} + 2\text{SO}_2\text{(g)}$

Step 2 (Reduction): The mercury(II) oxide is then reduced to mercury metal upon further heating.

$2\text{HgO(s)} \xrightarrow{\text{Heat}} 2\text{Hg(l)} + \text{O}_2\text{(g)}$

CinnabarHgSSulphide oreRoastingReductionHeatingHgOLiquid mercury

Marking Scheme

1Naming the ore (Cinnabar) and stating its form (Sulphide / HgS): 1 Mark
2Balanced chemical equation for the conversion of HgS to HgO with 'Heat' condition: 1 Mark
3Balanced chemical equation for the reduction of HgO to Hg with 'Heat' condition: 1 Mark

Hint

Think of the sulphide ore of mercury and how metals low in the reactivity series can be reduced to their metallic form by simple heating.

Quick Oral Answer

The ore of mercury is cinnabar, which is found as mercury(II) sulphide ( $\text{HgS}$ ). To extract mercury, cinnabar is heated in air to form mercury(II) oxide ( $\text{HgO}$ ), which on further heating decomposes to give liquid mercury.

Analysis & Explanation

Mercury is a metal low in the activity series. Metals low in the activity series are very unreactive, and their oxides can be reduced to metals by heating alone. Cinnabar ( $\text{HgS}$ ) is first heated in air (roasting) to convert it into mercury(II) oxide ( $\text{HgO}$ ). Upon further heating, $\text{HgO}$ undergoes thermal reduction to produce liquid mercury ( $\text{Hg}$ ). This demonstrates that highly unreactive metals do not require strong reducing agents like carbon; simple heating is sufficient.

Common Mistakes

1Writing the formula of cinnabar incorrectly as $\text{Hg}_2\text{S}$ instead of $\text{HgS}$ .
2Forgetting to write the state symbols or the reaction condition (Heat/ $\Delta$ ) over the arrow.
3Using carbon as a reducing agent for mercury oxide, which is unnecessary since simple heating is sufficient.

Interesting Facts

Mercury is the only metal that remains in a liquid state at room temperature.

Cinnabar has been mined since the Neolithic era and was historically used as a brilliant red pigment called vermilion.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2024?

This question carries 3 marks in the CBSE Class 10 Science 2024 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Metals and Non-metals" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Extraction of Metals" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2024 paper?

This is a Short Answer question from Section C in the CBSE Class 10 Science 2024 paper.