Which of the following statements is not correct ?
(a) Double bond is shorter than a single bond
(b) Sigma bond is weaker than a ???? (pi) bond
(c) Double bond is stronger than a single bond
(d) Covalent bond is stronger than hydrogen bond.
Answers
Answer:
A sigma bond is formed by end-to-end overlap of the bonding orbitals.
Whereas, a pi - bond is formed by side-to-side overlap of (usually) two p-orbitals. This places the electron density above and below the plane of the nuclei with a node in the middle. The nodal region reduces the degree to which the orbitals overlap, and therefore, a pi bond is weaker than a sigma bond between the same two elements.
Hydrogen bonds are a strong type of dipole-dipole interaction. As a Rule of Thumb, they are weaker than covalent and ionic ("intramolecular") bonds", but stronger than most dipole-dipole interactions.
Which of the following statements is not correct. Option B is incorrect option here.
Explanation:
(i) Double bond is always considered as more stronger as compared to single bond. Also the bond length of a double bond is around 1.34 ang. while that of a single bond is around 1.54 ang. If the bond length is more then it is weak and of the bond length is shorter it is stronger. So this statement is correct that double bond is shorter than single bond.
(ii) Sigma bond is weaker than Pi bond – now when comparing sigma bond and pi bond, the fact is that pi bonds are generally much weaker. This is because they have parallel orbital paths and the overlap is also much less. So this statement is wrong as Sigma bonds are much stronger than Pi bonds.
(iii) Double bond as already discussed above is much stronger as compared to single bond as the bond length in double bond is much shorter.
(iv) Covalent bond is stronger than hydrogen bond is also true as hydrogen bond is generally considered as a weak bond.
So the wrong statement here is option B – sigma bond is weaker than Pi bond.