Science — CBSE Class 10 board question

Cyclohexane (C₆H₁₂) has 6 carbon atoms arranged in a ring, each bonded to 2 hydrogen atoms with single covalent bonds:

$$\begin{array}{c}
\text{H}_2\text{C} - \text{CH}_2 \\
| \quad\quad\quad | \\
\text{H}_2\text{C} \quad \text{CH}_2 \\
| \quad\quad\quad | \\
\text{H}_2\text{C} - \text{CH}_2
\end{array}$$

Each C shares electrons with 2 C atoms and 2 H atoms (4 bond pairs, valency satisfied).

Source: Carbon and its Compounds, Section 4.2.2

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• Cyclohexane formula is C₆H₁₂ — examiners may deduct marks if you use the wrong formula.
• The key feature is the ring structure with all single bonds (saturated).
• In the electron dot structure, show 2 dots (shared pairs) for each C–C and C–H bond around all 6 carbons. Alternatively, the structural/line formula of the hexagonal ring with CH₂ at each carbon is accepted.
• Confirm all carbon valencies = 4 are satisfied (2 C–C bonds + 2 C–H bonds per carbon).