Chapter 11, Problem 11.46P

(a)

Interpretation Introduction

Interpretation:

$pH$ of pure $0.010M{\text{ NH}}_4\text{Cl}$ has to be calculated.

Concept Introduction:

The term $pH$ refers to concentration of $H^{+}$ ions in the solution.  A solution with less concentration of $H^{+}$ is basic and more concentration of $H^{+}$ is acidic.  The $pH$ scale is a measure of $1-14$ that a solution showing $pH\text{ 7}$ is neutral and above $7$ is basic, below $7$ is acidic.

(b)

Interpretation Introduction

Interpretation:

The indicator that titrates $HCl$ without the interference of $N{H}_4^{+}$ has to be chosen.

Concept Introduction:

Equivalence point ensures the titration reaction becomes completed and at this point the number of moles of titrant and the number of moles of analyte remain equal.  We cannot see the completion of titration reaction – the titrant and the analyte becoming equal in stoichiometric proportion, hence we use a chemical compound called indicator called which indicates the end of the reaction by color change.  The end point refers to the color change and indicates equivalence point has been reached.