Use the information and data given below to answer the questions (a) to (c):
• Stronger intermolecular forces result in a higher boiling point.
• Strength of London forces increases with the number of electrons in the
molecule.
• Boiling point of HF, HCl, HBr and HI is 293 K, 189 K, 206 K and
238 K respectively.
(a) Which type of intermolecular forces are present in the molecules
HF, HCl, HBr and HI?
(b) Looking at the trend of boiling points of HCl, HBr and HI, explain
out of dipole-dipole interaction and London interaction, which one
is predominant here.
(c) Why is the boiling point of hydrogen fluoride highest while that of
hydrogen chloride lowest?
(a) Since the halides are a polar molecule, due to the presence of permanent dipoles, the dipole-dipole interactions along with the London forces are found in these
halides (HF, HCl, HBr).
(b) The boiling point increases from HI to HCl (as I- is a very large ion, it is bonded by Van der Waal’s forces, so more energy is required to break the bonds. As the
size of the ions decreases, lesser energy is required). From this trend, we can conclude that London’s forces are predominant because these interactions also increase
from HF to HI.
(c) In HCl, size of Cl- ion is very small, due to which the bonded Van der Waal’s forces are very weak, so less energy is required to break the bonds. Thus the Boiling
point is the least.
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All Study Material
- JEE Main
- Exam Pattern
- Previous Year Papers
- PYQ Chapterwise
- Physics
- Kinematics 1D
- Kinemetics 2D
- Friction
- Work, Power, Energy
- Centre of Mass and Collision
- Rotational Dynamics
- Gravitation
- Calorimetry
- Elasticity
- Thermal Expansion
- Heat Transfer
- Kinetic Theory of Gases
- Thermodynamics
- Simple Harmonic Motion
- Wave on String
- Sound waves
- Fluid Mechanics
- Electrostatics
- Current Electricity
- Capacitor
- Magnetism and Matter
- Electromagnetic Induction
- Atomic Structure
- Dual Nature of Matter
- Nuclear Physics
- Radioactivity
- Semiconductors
- Communication System
- Error in Measurement & instruments
- Alternating Current
- Electromagnetic Waves
- Wave Optics
- X-Rays
- All Subjects
- Physics
- Motion in a Plane
- Law of Motion
- Work, Energy and Power
- Systems of Particles and Rotational Motion
- Gravitation
- Mechanical Properties of Solids
- Mechanical Properties of Fluids
- Thermal Properties of matter
- Thermodynamics
- Kinetic Theory
- Oscillations
- Waves
- Electric Charge and Fields
- Electrostatic Potential and Capacitance
- Current Electricity
- Thermoelectric Effects of Electric Current
- Heating Effects of Electric Current
- Moving Charges and Magnetism
- Magnetism and Matter
- Electromagnetic Induction
- Alternating Current
- Electromagnetic Wave
- Ray Optics and Optical Instruments
- Wave Optics
- Dual Nature of Radiation and Matter
- Atoms
- Nuclei
- Semiconductor Electronics: Materials, Devices and Simple Circuits.
- Chemical Effects of Electric Current,