Chapter 18, Problem 68A

How would you compare the strengths of two weak acids experimentally? By looking up information in a table or a handbook?

Interpretation Introduction

Interpretation:

The procedure to compare the strength of two weak acids experimentally is to be explained.

Concept introduction:

According to Arrhenius,

Acid is a substance which gives hydrogen ion in aqueous solution.

Depending upon release of hydrogen ion, an acid is categorized as weak or strong.

Answer to Problem 68A

Ionization constants of weak acids can be compared to know their strengths.

Explanation of Solution

Acid ionization constant tells about equilibrium that whether reactants are favored or products.

For a reaction,

$HA+H_{2}O\rightleftharpoons A^{-}+H_3{O}^{+}$

Acid ionization constant is given by:

$\begin{array}{l}{k}_a=\frac{\left[A^{-}\right]\times \left[H_3{O}^{+}\right]}{\left[HA\right]}\\ where,\\ \left[A^{-}\right]isconcentrationof{A}^{-}\\ \left[H_3{O}^{+}\right]isconcentrationof{H}_3{O}^{+}\\ \left[HA\right]isconcentrationofHA\end{array}$

More the value of acid ionization constant, more is the strength of acid.

Conclusion

Thus, acid ionization constant helps to compare two weak acids.