Write the net ionic equation for the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH).
A. H
+
(aq)+OH
−
(aq)→H
2
O(l)
B. Na
+
(aq)+Cl
−
(aq)→NaCl(aq)
C. HCl(aq)+NaOH(aq)→NaCl(aq)+H
2
O(l)
D. H
2
(g)+Cl
2
(g)→2HCl(g)
The Correct Answer and Explanation is :
The correct net ionic equation for the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) is:
A. ( \text{H}^+ \, (aq) + \text{OH}^- \, (aq) \rightarrow \text{H}_2\text{O} \, (l) )
Explanation
When hydrochloric acid (HCl) and sodium hydroxide (NaOH) react, they undergo a neutralization reaction, which is a common type of acid-base reaction. In this case, HCl, a strong acid, dissociates completely in water to form hydrogen ions (( \text{H}^+ )) and chloride ions (( \text{Cl}^- )):
[ \text{HCl} \, (aq) \rightarrow \text{H}^+ \, (aq) + \text{Cl}^- \, (aq) ]
Sodium hydroxide (NaOH), a strong base, also dissociates completely in water to produce sodium ions (( \text{Na}^+ )) and hydroxide ions (( \text{OH}^- )):
[ \text{NaOH} \, (aq) \rightarrow \text{Na}^+ \, (aq) + \text{OH}^- \, (aq) ]
In the reaction, the hydrogen ions from HCl react with the hydroxide ions from NaOH to form water:
[ \text{H}^+ \, (aq) + \text{OH}^- \, (aq) \rightarrow \text{H}_2\text{O} \, (l) ]
This equation represents the essence of the reaction and is called the net ionic equation because it shows only the ions that participate in the reaction, excluding the spectator ions (in this case, ( \text{Na}^+ ) and ( \text{Cl}^- )) that do not change during the reaction.
The complete ionic equation for the reaction would include all the ions involved:
[ \text{H}^+ \, (aq) + \text{Cl}^- \, (aq) + \text{Na}^+ \, (aq) + \text{OH}^- \, (aq) \rightarrow \text{Na}^+ \, (aq) + \text{Cl}^- \, (aq) + \text{H}_2\text{O} \, (l) ]
Upon canceling the spectator ions (( \text{Na}^+ ) and ( \text{Cl}^- )), we arrive at the net ionic equation. This net ionic equation is essential in understanding the fundamental process of neutralization, which results in the formation of water from the reaction of an acid and a base.