Download App

States of Matter — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryStates of Matter3 Marks
Question
Use the information and data given below to answer the questions (a) to (c):
  • Stronger intermolecular forces result in higher boiling point.
  • Strength of London forces increases with the number of electrons in the molecule.
  • Boiling point of HF, HCl, HBr and HI are 293 K, 189 K, 206 K and 238 K respectively.
  1. Which type of intermolecular forces are present in the molecules HF, HCl, HBr and HI?
  2. Looking at the trend of boiling points of HCl, HBr and HI, explain out of dipole interaction and London interaction, which one is predominant here.
  3. Why is boiling point of hydrogen fluoride highest while that of hydrogen chloride lowest?
✓

Answer

  1. HF → Hydrogen bonding HCl, HBr, HI→ Dipole-dipole interaction, London-dispersion force.
  2. London - dispersion force is dominant because boiling point is not in the order of decreasing electro negativity of halogens.
  3. HF involves strong intermolecular hydrogen bonding; hence its boiling point is highest.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from States of Matter→States of Matter — all question types→Chemistry STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

QUESTION Calculate bond energy of C - H bond if $\Delta_{ c } H$ of $CH _4$, is $-891 kJ mol { }^{-1}, \Delta_c H$ of $C ( s )$ is $-394 kJ mol ^{-1}, \Delta_c H ^{-}$of $H _2(g)$ is $-286 kJ Jol ^{-1}$, heat of sublimation of $C ( s )$ is $717 kJ mol ^{-1}$, heat of dissociation of $H _2$ is $436 kJ mol ^{-1}$.
→
Draw the shape of the following hybrid orbitals $\mathrm{sp}$,  $\mathrm{sp}^2$ and $\mathrm{sp}^3$.
→
How do atomic radius vary in a period and in a group? How do you explain the variation?
→
Describe the general trends in the following properties of the elements in Groups 13 and 14.
Atomic size.
→
Using the standard electrode potentials given in the Table, predict if the reaction between the following is feasible:

$\mathrm{Fe}^{3+}(\mathrm{aq})$ and $\mathrm{Cu}(\mathrm{s})$.
→
i. Name the class of hydrides to which $\mathrm{H}_2 \mathrm{O}$ and NaH belong.
ii. What is understood by hydride gap?
iii. What do you mean by 15 volume $\mathrm{H}_2 \mathrm{O}_2$ solution?
→
Calculate the mass and charge of one mole of electrons.
→
Use Lewis symbols to show electron transfer between the following atoms to form cations and anions: Ca and O
→
  1. 300ml. of oxygen at-10°C are heated to 10°C. Find the volume of gas at 10°C if pressure is constant.
  2. Name the temperature at which density of water is maximum.
→
1. Consider the same expansion, but this time against a constant external pressure of 1 atm.
2. What do you mean by entropy?
3. Air contains about $99 \%$ of $N _2$ and $O _2$ gases. Why they do not combine to form NO under the standard conditions? Standard Gibbs energy of formation of $NO ( g )$ is $86.7 kJ mol ^{-1}$.
→