Answered

Using Table 10.3, identify the stronger acid in each of the following pairs:

a. [tex]\( NH_4^{+} \)[/tex] or [tex]\( H_3O^{+} \)[/tex]

b. [tex]\( H_2SO_4 \)[/tex] or HCN

c. [tex]\( H_2O \)[/tex] or [tex]\( H_2CO_3 \)[/tex]



Answer :

Of course! Let's walk through each pair and identify the stronger acid.

### Part (a)
Compare [tex]$NH_4^+$[/tex] and [tex]$H_3O^+$[/tex]:

1. Ammonium ion ([tex]$NH_4^+$[/tex]): The ammonium ion is the conjugate acid of ammonia ([tex]$NH_3$[/tex]).
2. Hydronium ion ([tex]$H_3O^+$[/tex]): The hydronium ion is produced when an acid donates a proton to water. It is often considered as the measure of acidity in aqueous solutions.

In general, the hydronium ion ([tex]$H_3O^+$[/tex]) is a much stronger acid compared to the ammonium ion ([tex]$NH_4^+$[/tex]). Therefore:

[tex]$H_3O^+$[/tex] is the stronger acid.

### Part (b)
Compare [tex]$H_2SO_4$[/tex] and HCN:

1. Sulfuric acid ([tex]$H_2SO_4$[/tex]): Sulfuric acid is a very strong acid, known to dissociate completely in aqueous solutions (at least in its first dissociation step).
2. Hydrocyanic acid (HCN): Hydrocyanic acid is a weak acid, not dissociating completely in aqueous solutions.

Sulfuric acid ([tex]$H_2SO_4$[/tex]) is significantly stronger than hydrocyanic acid (HCN). Therefore:

[tex]$H_2SO_4$[/tex] is the stronger acid.

### Part (c)
Compare [tex]$H_2O$[/tex] and [tex]$H_2CO_3$[/tex]:

1. Water ([tex]$H_2O$[/tex]): Water can act as a very weak acid, donating protons to form hydroxide ions ([tex]$OH^-$[/tex]).
2. Carbonic acid ([tex]$H_2CO_3$[/tex]): Carbonic acid is a weak acid but stronger than water; it partially dissociates in water to produce bicarbonate ions ([tex]$HCO_3^-$[/tex]) and hydrogen ions ([tex]$H^+$[/tex]).

Carbonic acid ([tex]$H_2CO_3$[/tex]) is a stronger acid than water ([tex]$H_2O$[/tex]). Therefore:

[tex]$H_2CO_3$[/tex] is the stronger acid.

### Summary:
- (a) [tex]$H_3O^+$[/tex] is the stronger acid.
- (b) [tex]$H_2SO_4$[/tex] is the stronger acid.
- (c) [tex]$H_2CO_3$[/tex] is the stronger acid.