A shining metal 'M', on burning gives a dazzling white flame and changes to a white powder 'N'.

(a) Identify 'M' and 'N'.

(b) Represent the above reaction in the form of a balanced chemical equation.

(c) Does 'M' undergo oxidation or reduction in this reaction? Justify.

Q: A shining metal 'M', on burning gives a dazzling white flame and changes to a white powder 'N'. (a) Identify 'M' and 'N'. (b) Represent the above reaction in the form of a balanced chemical equation. (c) Does 'M' undergo oxidation or reduction in this reaction? Justify.

(a) Metal **'M'** is **Magnesium** ($Mg$) and the white powder **'N'** is **Magnesium oxide** ($MgO$). (b) The balanced chemical equation for the reaction is: $$2\text{Mg}(\text{s}) + \text{O}_2(\text{g}) \rightarrow 2\text{MgO}(\text{s})$$ (c) Metal **'M'** (Magnesium) undergoes **oxidation** in this reaction. **Justification:** Oxidation is defined as the gain of oxygen by a substance. Here, magnesium ($Mg$) reacts with oxygen ($O_2$) to gain oxygen atoms and form magnesium oxide ($MgO$). Therefore, magnesium is oxidized.

Chemical Reactions and Equations

Burning of Magnesium Ribbon

Official Answer

(a) Metal 'M' is Magnesium ( $Mg$ ) and the white powder 'N' is Magnesium oxide ( $MgO$ ).

(b) The balanced chemical equation for the reaction is:

$2\text{Mg}(\text{s}) + \text{O}_2(\text{g}) \rightarrow 2\text{MgO}(\text{s})$

Justification: Oxidation is defined as the gain of oxygen by a substance. Here, magnesium ( $Mg$ ) reacts with oxygen ( $O_2$ ) to gain oxygen atoms and form magnesium oxide ( $MgO$ ). Therefore, magnesium is oxidized.

MagnesiumMagnesium oxideoxidationgain of oxygen2Mg + O2 -> 2MgO

Marking Scheme

10.5 mark for identifying M as Magnesium
20.5 mark for identifying N as Magnesium oxide
31.0 mark for writing the balanced chemical equation with state symbols
41.0 mark for identifying oxidation with proper justification

Common Mistakes

1Writing an unbalanced equation like $Mg + O_2 \rightarrow MgO$ .
2Forgetting to write physical state symbols like (s) and (g).
3Confusing oxidation with reduction.

Interesting Facts

Magnesium burns with such an intense, dazzling white light that it is used in fireworks, marine flares, and was historically used as a flash for photography!

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2020?

This question carries 3 marks in the CBSE Class 10 Science 2020 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Chemical Reactions and Equations" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Burning of Magnesium Ribbon" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2020 paper?

This is a Short Answer question from Section B in the CBSE Class 10 Science 2020 paper.