/*! 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 18 You have 0.10-mol samples of thr... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 17: Problem 18

You have 0.10-mol samples of three acids identified simply as HX, HY, and HZ. For each acid, you make up \(0.10 M\) solutions by adding sufficient water to each of the acid samples. When you measure the \(\mathrm{pH}\) of these samples, you find that the \(\mathrm{pH}\) of \(\mathrm{HX}\) is greater than the \(\mathrm{pH}\) of \(\mathrm{HY}\), which in turn is greater than the \(\mathrm{pH}\) of \(\mathrm{HZ}\). a. Which of the acids is the least ionized in its solution? b. Which acid has the largest \(K_{a}\) ?

Short Answer

Expert verified
HX is the least ionized, and HZ has the largest \( K_a \).

Step by step solution

01

Understanding pH and Acid Ionization

The pH of a solution indicates its acidity; the lower the pH, the stronger the acid. Stronger acids ionize more fully in water, producing more hydrogen ions ( H^+ ) and thus a lower pH.
02

Analyzing pH Order

According to the problem, \(\text{pH of HX} > \text{pH of HY} > \text{pH of HZ}\).This means that HX is the weakest acid (least ionized), and HZ is the strongest acid (most ionized). HY's acidity falls between HX and HZ.
03

Definitions and Relationships

The ionization constant of an acid ( K_a ) signifies its strength; a larger K_a means higher ionization and a stronger acid. Therefore, the acid with the smallest pH will have the largest K_a .
04

Determining Least Ionized Acid

Since HX has the highest pH, it ionizes the least in water. It releases fewer H^+ ions compared to HY and HZ.
05

Determining Largest Ka

HZ, with the lowest pH, ionizes the most in its solution. Consequently, HZ has the largest K_a value among the acids.

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!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Ionization Constant
Every acid has a unique characteristic known as its ionization constant, denoted as \( K_a \). This constant provides insights into how readily an acid ionizes in solution. When an acid is placed in water, it partially ionizes and releases hydrogen ions (\( H^+ \)). The scale of this ionization process is represented by \( K_a \). Generally:
  • The larger the \( K_a \), the more an acid dissociates into ions, and therefore, it is a stronger acid.
  • If \( K_a \) is small, the acid does not ionize much, indicating a weaker acid.
Essentially, \( K_a \) reflects the strength of the acid by showing the extent of its ionization. By comparing acids like HX, HY, and HZ, we can determine that the acid with the lowest \( K_a \) ionizes the least and therefore is the weakest among them.
pH Scale
The pH scale is a numeric scale used to specify the acidity or basicity of a solution. It ranges from 0 to 14, with:
  • 0-6 indicating acidic solutions.
  • 7 being neutral (pure water).
  • 8-14 indicating basic solutions.
The lower the pH, the more acidic the solution is, and thus it contains more \( H^+ \) ions. For the acids HX, HY, and HZ:
  • The acid with the highest pH is the least acidic.
  • The acid with the lowest pH is the most acidic and is the strongest in terms of ionization.
Hence, the order pH of \( \text{HX} > \text{pH of HY} > \text{pH of HZ} \) tells us about their relative strength where HX is the weakest and HZ is the strongest.
Acid Strength
Acid strength is determined by how completely an acid ionizes in solution. Strong acids dissociate completely, releasing a significant amount of \( H^+ \) ions, while weak acids only partially ionize:
  • Strong acids have high \( K_a \) values and low pH levels.
  • Weak acids have low \( K_a \) values and relatively higher pH levels.
For the provided scenario:
  • HX is the least ionized and therefore has the lowest acid strength among the three acids.
  • HZ, being the most ionized with the largest \( K_a \), is the strongest acid.
Understanding the relationship between \( K_a \), pH, and ionization helps in determining each acid's strength, critical for predicting their behavior in chemical reactions.

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

A chemist needs a buffer with \(\mathrm{pH}\) 3.50. How many milliliters of pure formic acid (density \(=1.220 \mathrm{~g} / \mathrm{mL}\) ) must be added to \(325 \mathrm{~mL}\) of \(0.0857 \mathrm{M} \mathrm{NaOH}\) solution to obtain such a buffer?

Malic acid is a weak diprotic organic acid with \(K_{a 1}=\) \(4.0 \times 10^{-4}\) and \(K_{a 2}=9.0 \times 10^{-6}\) a. Letting the symbol \(\mathrm{H}_{2} \mathrm{~A}\) represent malic acid, write the chemical equations that represent \(K_{a 1}\) and \(K_{a 2} .\) Write the chemical equation that represents \(K_{a 1} \times K_{a 2}\) b. Qualitatively describe the relative concentrations of \(\mathrm{H}_{2} \mathrm{~A}\), \(\mathrm{HA}^{-}, \mathrm{A}^{2-}\), and \(\mathrm{H}_{3} \mathrm{O}^{+}\) in a solution that is about one molar in malic acid. c. Calculate the \(\mathrm{pH}\) of a \(0.0100 \mathrm{M}\) malic acid solution and the equilibrium concentration of \(\left[\mathrm{H}_{2} \mathrm{~A}\right]\). d. What is the \(A^{2-}\) concentration?

What is the concentration of oxalate ion, \(\mathrm{C}_{2} \mathrm{O}_{4}^{2-}\), in \(0.10 M\) oxalic acid, \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\) ? \(K_{a 1}\) is \(5.6 \times 10^{-2}\), and \(K_{a 2}\) is \(5.1 \times 10^{-5}\)

A friend of yours has performed three titrations: strong acid with a strong base, weak acid with a strong base, and a weak base with a strong acid. He hands you the three titration curves, saying he has forgotten which is which. What attributes of the curves would you look at to correctly identify each curve?

What is the \(\mathrm{pH}\) of a solution that is \(0.10 \mathrm{M} \mathrm{KNO}_{2}\) and \(0.15 \mathrm{M} \mathrm{HNO}_{2}\) (nitrous acid)?
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Reactions

Read Explanation

Physical Chemistry

Read Explanation

Chemical Analysis

Read Explanation

Nuclear Chemistry

Read Explanation

Kinetics

Read Explanation

The Earths Atmosphere

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.