What is the total number of covalent bonds in methanol?
- (a)3
- (b)4
- (c)5
- (d)6
Correct — C, 5. Methanol has the formula CH₃OH. Drawing its structure, the carbon atom forms three C–H bonds and one C–O bond, while the oxygen forms one O–H bond. Adding them up: 3 (C–H) + 1 (C–O) + 1 (O–H) = 5 single covalent bonds in the molecule. Every bond is a shared pair of electrons, which keeps carbon's valency at 4, oxygen's at 2 and each hydrogen's at 1.
- (a)3 — This counts only the three C–H bonds and ignores the C–O and O–H bonds.
- (b)4 — Counting the three C–H bonds plus one of the remaining bonds still misses one; methanol has five covalent bonds, not four.
- (d)6 — Overcounts — likely from treating the C–O bond as a double bond; in methanol the C–O bond is a single bond.
A covalent bond is a shared pair of electrons between two atoms. Counting the covalent bonds in a molecule means drawing its structural formula and totalling the atom-to-atom connections. In methanol (CH₃OH), all bonds are single covalent bonds.
The reliable method is to expand the condensed formula: CH₃OH is H–C(H)(H)–O–H. Carbon uses all four of its bonds (three to H, one to O), oxygen uses two (one to C, one to H), and each hydrogen uses one. The tempting error is to forget the O–H bond or to over-count by imagining a C=O double bond.
- Methanol is CH₃OH, the simplest alcohol.
- Bond inventory: 3 C–H bonds, 1 C–O bond, 1 O–H bond.
- Total = 5 single covalent bonds.
- Valencies satisfied: carbon 4, oxygen 2, each hydrogen 1.
Adding the C–H, C–O and O–H single bonds gives 5, so the answer is (c).
- Forgetting the O–H bond and counting only four bonds.
- Imagining a C=O double bond and over-counting to six.
Asked as the total number of covalent bonds in a named molecule — solved by drawing the structure and counting atom-to-atom connections.
No directly related past PYQ was found.
- practice — not a real PYQ
The total number of covalent bonds in a molecule of methane (CH₄) is
- (a)2
- (b)3
- (c)4
- (d)5
Answer(c) 4 — carbon forms four single C–H bonds.
- practice — not a real PYQ
In a molecule of water (H₂O), the number of covalent bonds is
- (a)1
- (b)2
- (c)3
- (d)4
Answer(b) 2 — oxygen forms two O–H single bonds.