Chapter 4 · Carbon and its Compounds

NCERT Class 10 Science Chapter 4 Intext Questions (Page 61)

All 2 questions of NCERT Class 10 Science Chapter 4 Intext Questions (Page 61) — Carbon and its Compounds — in the book's order, each with its answer and a step-by-step solution.

1. Q1
   What would be ​the electron dot structure ​of carbon ​dioxide ​which has ​the ​formula ${\text{CO}}_2$?
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   Carbon shares two electron pairs with each oxygen, giving $\text{O}=\text{C}=\text{O}$ with two lone pairs on each oxygen; every atom has an octet.

   The carbon atom sits between the two oxygen atoms and shares two pairs of electrons with each of them, so carbon dioxide has two double bonds, $\text{O}=\text{C}=\text{O}$. Each oxygen atom also keeps two lone pairs (four unshared electrons), while the carbon has none. The structure shows all $16$ valence electrons ($4$ from carbon and $6$ from each oxygen) as $4$ shared pairs and $4$ lone pairs, and every atom has a complete octet.

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2. Q2
   What would be the electron dot structure ​of ​a molecule of sulphur which is made up of ​eight atoms of sulphur? ​(Hint ​– The eight atoms of ​sulphur are ​joined together in the ​form of a ring.)
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   Eight S atoms form a ring; each shares one electron pair with each of its two neighbours and keeps two lone pairs.

   The eight sulphur atoms form a closed ring in which every sulphur atom is joined to its two neighbours by a single covalent bond — one shared pair of electrons on each side — and keeps its remaining four valence electrons as two lone pairs. Sulphur $(2,8,6)$ needs two electrons, and two single bonds to two different atoms give it an octet: $2$ shared pairs $+2$ lone pairs $=8$ electrons. The whole ${\text{S}}_8$ molecule shows $8\times 6=48$ valence electrons as $8$ shared pairs (the ring bonds) and $16$ lone pairs.

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