/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 31 A number of salts containing the... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 11: Problem 31

A number of salts containing the tetrahedral polyatomic anion, \(\mathrm{BF}_{4}^{-}\), are ionic liquids, whereas salts containing the somewhat larger tetrahedral ion \(\mathrm{SO}_{4}{ }^{2-}\) do not form ionic liquids. Explain this observation.

Short Answer

Expert verified
In short, salts containing the tetrahedral polyatomic anion \(\mathrm{BF}_{4}^{-}\) form ionic liquids due to the weaker intermolecular forces and less polar nature of this ion compared to the somewhat larger tetrahedral ion \(\mathrm{SO}_{4}{ }^{2-}\). The lower polarity of \(\mathrm{BF}_{4}^{-}\) results in weaker interactions between the ions, allowing them to move more easily in the liquid phase. In contrast, the higher polarity of \(\mathrm{SO}_{4}{ }^{2-}\) strengthens the interactions between ions, leading to higher melting points and a lack of ionic liquid formation.

Step by step solution

01

Ionic Liquids

First, let's understand what ionic liquids are. Ionic liquids are salts that are typically a liquid at or below room temperature, having low melting points. This is due to their ionic nature, which allows them to remain in the liquid phase as a result of weak intermolecular forces between ions in the liquid.
02

Analyzing Tetrahedral Structures

When looking at the two ions given, both have tetrahedral structures. The slightly smaller tetrahedral ion, \(\mathrm{BF}_{4}^{-}\), has boron at the central atom, surrounded by four fluorine atoms. The larger tetrahedral ion, \(\mathrm{SO}_{4}{ }^{2-}\), has sulfur at the central atom, surrounded by four oxygen atoms.
03

Comparing Electronegativity

The electronegativity difference between boron and fluorine in \(\mathrm{BF}_{4}^{-}\) is smaller compared to the difference between sulfur and oxygen in \(\mathrm{SO}_{4}{ }^{2-}\). This is because boron has an electronegativity of 2.0, while fluorine is the most electronegative element with a value of 3.98. Meanwhile, sulfur has an electronegativity of 2.58, and oxygen has an electronegativity value of 3.44. Therefore, the \(\mathrm{BF}_{4}^{-}\) ion has a more evenly distributed electron density than \(\mathrm{SO}_{4}{ }^{2-}\).
04

Examining Ionic Bonding and Intermolecular Forces

Both anions are equally symmetrical in shape (tetrahedral), but \(\mathrm{BF}_{4}^{-}\) is much less polar than \(\mathrm{SO}_{4}{ }^{2-}\). The lower polarity of \(\mathrm{BF}_{4}^{-}\) results in weaker intermolecular forces (IMFs) such as dipole-dipole interactions or hydrogen bonding, allowing the ions to slide past each other more easily. In contrast, \(\mathrm{SO}_{4}{ }^{2-}\) exhibits stronger IMFs due to its higher polarity, which increases its melting point, making it harder to form ionic liquids.
05

Conclusion

In conclusion, salts containing the tetrahedral polyatomic anion \(\mathrm{BF}_{4}^{-}\) form ionic liquids because of the weaker intermolecular forces and less polar nature of this ion compared to the somewhat larger tetrahedral ion \(\mathrm{SO}_{4}{ }^{2-}\). The lower polarity of \(\mathrm{BF}_{4}^{-}\) results in weaker interactions between the ions, allowing them to move more easily in the liquid phase, while the higher polarity of \(\mathrm{SO}_{4}{ }^{2-}\) strengthens the interactions between ions, leading to higher melting points and a lack of ionic liquid formation.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

For many years drinking water has been cooled in hot climates by evaporating it from the surfaces of canvas bags or porous clay pots. How many grams of water can be cooled from 35 to \(20^{\circ} \mathrm{C}\) by the evaporation of \(60 \mathrm{~g}\) of water? (The heat of vaporization of water in this temperature range is \(2.4 \mathrm{~kJ} / \mathrm{g}\). The specific heat of water is \(4.18 \mathrm{~J} / \mathrm{g}-\mathrm{K}\).)

The following data present the temperatures at which certain vapor pressures are achieved for dichloromethane \(\left(\mathrm{CH}_{2} \mathrm{Cl}_{2}\right)\) and methyl iodide \(\left(\mathrm{CH}_{3} \mathrm{I}\right)\) : (a) Which of the two substances is expected to have the greater dipole-dipole forces? Which is expected to have the greater dispersion forces? Based on your answers, explain why it is difficult to predict which compound would be more volatile. (b) Which compound would you expect to have the higher boiling point? Check your answer in a reference book such as the CRC Handbook of Chemistry and Physics. (c) The order of volatility of these two substances changes as the temperature is increased. What quantity must be different for the two substances for this phenomenon to occur? (d) Substantiate your answer for part (c) by drawing an appropriate graph.

List the three states of matter in order of (a) increasing molecular disorder and (b) increasing intermolecular attraction. (c) Which state of matter is most easily compressed?

At standard temperature and pressure the molar volumes of \(\mathrm{Cl}_{2}\) and \(\mathrm{NH}_{3}\) gases are \(22.06\) and \(22.40 \mathrm{~L}\), respectively. (a) Given the different molecular weights, dipole moments, and molecular shapes, why are their molar volumes nearly the same? (b) On cooling to \(160 \mathrm{~K}\), both substances form crystalline solids. Do you expect the molar volumes to decrease or increase on cooling the gases to \(160 \mathrm{~K}\) ? (c) The densities of crystalline \(\mathrm{Cl}_{2}\) and \(\mathrm{NH}_{3}\) at \(160 \mathrm{~K}\) are \(2.02\) and \(0.84 \mathrm{~g} / \mathrm{cm}^{3}\), respectively. Calculate their molar volumes. (d) Are the molar volumes in the solid state as similar as they are in the gaseous state? Explain. (e) Would you expect the molar volumes in the liquid state to be closer to those in the solid or gaseous state?

Hydrazine \(\left(\mathrm{H}_{2} \mathrm{NNH}_{2}\right)\), hydrogen peroxide (HOOH), and water \(\left(\mathrm{H}_{2} \mathrm{O}\right)\) all have exceptionally high surface tensions compared with other substances of comparable molecular weights. (a) Draw the Lewis structures for these three compounds. (b) What structural property do these substances have in common, and how might that account for the high surface tensions?
See all solutions

Recommended explanations on Chemistry Textbooks

Ionic and Molecular Compounds

Read Explanation

Nuclear Chemistry

Read Explanation

Inorganic Chemistry

Read Explanation

Organic Chemistry

Read Explanation

Chemistry Branches

Read Explanation

Chemical Analysis

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.