Hydroxide and hydrochloric acid

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Hydroxide and hydrochloric acid? a. OH-(aq) + H+(aq) à H2O(l) b. NaOH(aq) + HCl(aq) à NaCl(aq) + H2O(l) c. Na+(aq) + Cl-(aq) à NaCl(aq) d. OH- + H+ à H2O
Which of the following represents the net ionic equation for the acid/base reaction between sodium hydroxide and hydrochloric acid? a. OH-(aq) + H+(aq) à H2O(l) b. NaOH(aq) + HCl(aq) à NaCl(aq) + H2O(l) c. Na+(aq) + Cl-(aq) à NaCl(aq) d. OH- + H+ à H2O

The Correct Answer and Explanation is:

The correct net ionic equation for the acid/base reaction between sodium hydroxide (NaOH) and hydrochloric acid (HCl) is:

a. OH-(aq) + H+(aq) → H2O(l)

Explanation:

  1. Understanding the Reaction:
    When sodium hydroxide (NaOH), a strong base, reacts with hydrochloric acid (HCl), a strong acid, they undergo a neutralization reaction. This reaction results in the formation of water (H2O) and sodium chloride (NaCl), a salt. The complete equation is: NaOH(aq)+HCl(aq)→NaCl(aq)+H2O(l)NaOH(aq) + HCl(aq) \rightarrow NaCl(aq) + H2O(l)NaOH(aq)+HCl(aq)→NaCl(aq)+H2O(l)
  2. Breaking Down the Ionic Components:
    Both NaOH and HCl dissociate fully in water because they are strong electrolytes. This means the equation can be written in terms of their ions:
    • NaOH → Na+(aq) + OH-(aq)
    • HCl → H+(aq) + Cl-(aq)
    Substituting these into the reaction gives: Na+(aq)+OH−(aq)+H+(aq)+Cl−(aq)→Na+(aq)+Cl−(aq)+H2O(l)Na+(aq) + OH-(aq) + H+(aq) + Cl-(aq) \rightarrow Na+(aq) + Cl-(aq) + H2O(l)Na+(aq)+OH−(aq)+H+(aq)+Cl−(aq)→Na+(aq)+Cl−(aq)+H2O(l)
  3. Identifying the Spectator Ions:
    In the above equation, the sodium ion (Na+) and chloride ion (Cl-) are spectator ions, meaning they do not participate in the actual chemical change. They appear on both sides of the equation without being altered.
  4. Net Ionic Equation:
    By removing the spectator ions, the net ionic equation focuses on the actual reaction that occurs, which is the combination of hydroxide ions (OH-) from NaOH and hydrogen ions (H+) from HCl to form water: OH−(aq)+H+(aq)→H2O(l)OH-(aq) + H+(aq) \rightarrow H2O(l)OH−(aq)+H+(aq)→H2O(l) This equation shows the essence of the acid/base neutralization process, where hydroxide ions (a base) combine with hydrogen ions (an acid) to produce water.

Other Answer Choices:

  • b. NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l): This is the complete molecular equation but does not represent the net ionic equation.
  • c. Na+(aq) + Cl-(aq) → NaCl(aq): This shows the dissociation of sodium chloride in solution, but it doesn’t represent the acid/base reaction.
  • d. OH- + H+ → H2O: This is similar to option a, but it is missing the aqueous state notation for the ions. However, it’s essentially the same equation.

The net ionic equation is the most simplified form that focuses on the actual chemical change, leaving out the spectator ions.

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