Free Sigma and Pi Bonds MCQs with Answers
34 Sigma and Pi Bonds MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
A sigma bond forms by direct end-to-end overlap along the internuclear axis, whereas a pi bond forms by sideways overlap of parallel orbitals. The topic covers single, double and triple bonds, bond composition, restricted rotation and the relation between sigma and pi bonding and orbital hybridisation.
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- A. sideways overlap of two p orbitals
- B. head on overlap of two orbitals along the axis joining the nuclei
- C. the transfer of electrons from one atom to another
- D. attraction between two ions
Explanation: End on overlap concentrates electron density directly between the nuclei, which makes a sigma bond stronger than a pi bond and allows free…
Correct answer: head on overlap of two orbitals along the axis joining the nuclei- A. three sigma and two pi
- B. two sigma and three pi
- C. five sigma and no pi
- D. four sigma and one pi
Explanation: The two carbon to hydrogen bonds are sigma, and the carbon to carbon triple bond consists of one sigma plus two pi bonds, giving three…
Correct answer: three sigma and two pi- A. the sigma bond is too strong
- B. the atoms are too heavy
- C. turning one carbon would break the sideways overlap of the pi bond
- D. double bonds are ionic
Explanation: The pi bond depends on two parallel p orbitals overlapping sideways, and rotating one carbon by ninety degrees would destroy that overlap…
Correct answer: turning one carbon would break the sideways overlap of the pi bond- A. two sigma bonds
- B. two pi bonds
- C. one sigma bond formed by sp2 overlap and one pi bond formed by sideways overlap of unhybridised p orbitals
- D. one ionic and one covalent bond
Explanation: Each carbon uses three sp2 hybrids for sigma bonds to two hydrogens and to the other carbon, and the leftover p orbital on each overlaps…
Correct answer: one sigma bond formed by sp2 overlap and one pi bond formed by sideways overlap of unhybridised p orbitals- A. both shared electrons come from the same atom
- B. no electrons are shared
- C. it is much weaker than a normal covalent bond
- D. it involves the transfer of electrons
Explanation: One atom supplies the whole electron pair while the other provides an empty orbital, as when ammonia donates its lone pair to a hydrogen…
Correct answer: both shared electrons come from the same atom- A. two sigma and two pi
- B. four sigma and no pi
- C. two sigma and four pi
- D. one sigma and three pi
Explanation: Each of the two carbon to oxygen double bonds contributes one sigma and one pi bond, giving two of each in total.
Correct answer: two sigma and two pi- A. it involves fewer electrons
- B. sideways overlap of p orbitals is less effective than head on overlap
- C. it is formed between different elements
- D. it has no electron density
Explanation: Sideways overlap concentrates less electron density between the nuclei than end on overlap does, so the pi bond is easier to break, which…
Correct answer: sideways overlap of p orbitals is less effective than head on overlap- A. the dative bond breaks immediately
- B. once formed, the origin of the electron pair no longer affects the bond
- C. nitrogen changes its hybridisation
- D. one hydrogen leaves the ion
Explanation: A bond is defined by the shared pair between the two nuclei, not by which atom supplied the electrons, so experimentally the four bonds…
Correct answer: once formed, the origin of the electron pair no longer affects the bond- A. s-orbitals
- B. p-orbitals
- C. sp3 hybrid orbitals
- D. sp2 hybrid orbitals
Explanation: Each doubly bonded carbon uses three sp2 hybrids for its sigma bonds and keeps one unhybridised p orbital, and the sideways overlap of…
Correct answer: p-orbitals- A. MOT
- B. VBT
- C. VSEPR
- D. CFT
Explanation: Crystal field theory deals with how the d orbitals of a transition metal ion are split by the surrounding ligands, so it explains colour…
Correct answer: CFT- A. 5 sigma bonds
- B. 4 sigma and 1 pi bonds
- C. 3 sigma and 2 pi bonds
- D. 2 sigma and 3 pi bonds
Explanation: Acetylene has the structure H-C≡C-H. Each C-H bond is one sigma bond, and the carbon-carbon triple bond contains one sigma bond plus two…
Correct answer: 3 sigma and 2 pi bonds- A. Single covalent bond
- B. Hydrogen bond
- C. Double covalent bond
- D. Coordinate covalent bond
Explanation: A coordinate covalent bond forms when one species donates both electrons of the shared electron pair, although the pair is then shared by…
Correct answer: Coordinate covalent bond- A. 2
- B. 1
- C. 3
- D. 4
Explanation: In N2, the three shared electron pairs consist of one sigma bond and two pi bonds, so the bond order is 3.
Correct answer: 3- A. Bonding molecular orbital
- B. Antibonding molecular orbital
- C. Hybrid orbital
- D. Super atomic orbital
Explanation: An antibonding molecular orbital results from destructive overlap and lies at higher energy than the combining atomic orbitals.
Correct answer: Antibonding molecular orbital- A. Un-hybrid orbitals
- B. Hybrid orbitals
- C. Hybrid and un hybrid orbitals
- D. atomic orbital and hybrid orbital
Explanation: A pi bond forms by sideways overlap of parallel, unhybridized atomic orbitals, usually p orbitals, above and below the internuclear axis.
Correct answer: Un-hybrid orbitals- A. Bond
- B. Attractive force
- C. Interaction
- D. All of above represent same entity
Explanation: The attractive force that holds atoms together in a compound through electron sharing or transfer is called a chemical bond.
Correct answer: Bond- A. Pi
- B. Sigma
- C. Both
- D. Neither
Explanation: Two p orbitals can overlap end-to-end along the internuclear axis to form a sigma bond, or side-by-side to form a pi bond.
Correct answer: Both- A. propene
- B. butanoic acid
- C. butanal
- D. ethoxy ethane
Explanation: Ethoxy ethane, CH3CH2-O-CH2CH3, contains only single bonds, and every single bond is a sigma bond.
Correct answer: ethoxy ethane- A. Two sigma bonds
- B. Two Pi bonds
- C. One sigma and one Pi bonds
- D. One sigma and two Pi bonds
Explanation: A double bond consists of one sigma bond formed by head-on orbital overlap and one pi bond formed by sideways overlap of p orbitals.
Correct answer: One sigma and one Pi bonds- A. 1
- B. 2
- C. 3
- D. 4
Explanation: Carbon monoxide, or CO, has one carbon atom and one oxygen atom. In its Lewis dot structure, the carbon atom is triple-bonded to the…
Correct answer: 3Sigma and Pi Bonds MCQs: common questions
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