Exams › JEE Main › Chemistry

Two statements are given below, one labelled Assertion (A) and the other Reason (R). Assertion A: Dipole-dipole interactions are the only non-covalent interactions responsible for hydrogen bond formation. Reason R: Fluorine is the most electronegative element and the hydrogen bonds in HF are symmetrical. Choose the most appropriate option.

1. A is false but R is true
2. Both A and R are true and R is the correct explanation of A
3. A is true R is false
4. Both A and R are true but R is NOT the correct explanation of A

Correct answer: A is true R is false

Solution

Hydrogen bonding is essentially an electrostatic dipole-dipole type interaction, so A is taken as true; however the hydrogen bonds in HF are not symmetrical, so R is false.

Related JEE Main Chemistry questions

• Although the electronegativity gap between N and F is larger than that between N and H, ammonia has a dipole moment of 1.5 D while nitrogen trifluoride has only 0.2 D. The reason is that
• When N₂ is converted into N₂⁺, the dissociation energy of the N–N bond ______, and when O₂ is converted into O₂⁺, the dissociation energy of the O–O bond ______.
• From the ions listed below, which pair has geometries that can be accounted for by the same type of orbital hybridization? NO₂⁻, NO₃⁻, NH₂⁻, NH₄⁺, SCN⁻
• Atoms A and B have electronegativities of 1.20 and 4.0, respectively. What is the percentage ionic character of the A–B bond?
• In the phosphate ion, PO₄³⁻, what is the formal charge on an oxygen atom that is singly bonded to phosphorus in a P–O bond?
• Among the following species, which one has no unpaired electrons?

⚔️ Practice JEE Main Chemistry free + battle 1v1 →