   Chapter 16, Problem 44PS

Chapter
Section
Textbook Problem

Equal molar quantities of ammonia and sodium dihydrogen phosphate (NaH2PO4) are mixed. (a) Write a balanced, net ionic equation for the acid-base reaction that can, in principle, occur. (b) Does the equilibrium lie to the right or left?

(a)

Interpretation Introduction

Interpretation: The balanced, net ionic equation is to be written for the mixture of ammonia (NH3) and sodium hydrogen phosphate (NaH2PO4)

Concept introduction:

Balanced reaction is a chemical reaction in which number of atoms for each element in the reaction and the total charge are same on both reactant side and the product side.

Steps in balancing the information

• Step 1: Write the unbalanced equation
• Step 2: Find the coefficient to balance the equation.
• The coefficient should be reduced to the smallest whole number
Explanation

The reaction between sodium dihydrogen phosphate (NaH2PO4) and ammonia (NH3) is an acid-base reaction.

Sodium dihydrogen phosphate is amphoteric in nature. It means that it can act either as an acid or a base depending on the substance it reacts with. The amphoteric part of the acid is hydrogen phosphate dianion HPO42-. Here, in this reaction, it acts as an acid in the presence of ammonia.

Equimolar amounts of acid and base are mixed. Ammonia acts as a base and it forms the conjugate acid NH4+. Sodium dihydrogen phosphate acts as an acid and forms conjugate base PO43. This reaction exists in chemical equilibrium because sodium dihydrogen phosphate is a weak acid and it does not dissociate completely to give the products

(b)

Interpretation Introduction

Interpretation: The direction of the equilibrium for the given reaction is to be determined.

Concept introduction: An acid-base reaction reaction is represented as written below.

HA(aq)+B(aq)   BH+(aq)  +    A(aq)(acid)    (base)        (conjugate     acid)   (conjugate     base)

The base will take up the proton from acid and form its conjugate acid and simultaneously acid will form its conjugate base. The equilibrium will be forward or backward can be determined by using the dissociation constants (Kaand Kb) for reactants as well as of the products. The more the value of Ka for an acid, stronger will be the acid and it will undergo faster ionization. Similarly, higher the value of Kb for a base, stronger will be the base and it will undergo faster ionization.

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started 