Chapter 18, Problem 65A

Explain the difference between a strong acid and a weak acid.

Interpretation Introduction

Interpretation:

The difference between strong acid and weak acid is to be explained.

Concept introduction:

According to Arrhenius,

Acid is a substance which gives hydrogen ion and Base is a substance which gives hydroxyl ions in aqueous solution.

Answer to Problem 65A

Strong acid ionizes completely into its ions in aqueous solution but weak acid ionizes to some extent in aqueous solution.

For example $HI$ is strong acid and $HCOOH$ is weak acid.

Explanation of Solution

Thus, strong acids are completely dissociated but weak acids dissociated to a particular extent according to its strength.

For example:

When $HI$ is dissolved in water, the equation is given as:

$HI+H_{2}O\to I^{-}+H_3{O}^{+}$

$HI$ is strong acid so it is completely dissolved.

But $HCOOH$ is weak acid, it remains in equilibrium with dissociated ions on dissolution as:

$HCOOH+H_{2}O\rightleftharpoons HCO{O}^{-}+H_3{O}^{+}$

Conclusion

When $HI$ is dissolved in water, contents in solution are: $H_3{O}^{+}and{I}^{-}$

When $HCOOH$ is dissolved in water, contents in solution are: $HCOOH,H_3{O}^{+}andHCO{O}^{-}$