To determine what is missing in the neutralization reaction [tex]\( \text{HBr} + \text{KOH} \rightarrow \text{H}_2\text{O} + \quad \)[/tex], let's analyze the balanced equation step by step.
1. Identify the reactants and products:
- The reactants are hydrobromic acid ([tex]\(\text{HBr}\)[/tex]) and potassium hydroxide ([tex]\(\text{KOH}\)[/tex]).
- The products of a typical acid-base neutralization reaction are generally water ([tex]\(\text{H}_2\text{O}\)[/tex]) and a salt.
2. Predict the salt formed:
- In this reaction, [tex]\(\text{HBr}\)[/tex] (an acid) reacts with [tex]\(\text{KOH}\)[/tex] (a base).
- When these two react, [tex]\(\text{H}_+ \)[/tex] from [tex]\(\text{HBr}\)[/tex] combines with [tex]\(\text{OH}^-\)[/tex] from [tex]\(\text{KOH}\)[/tex] to form [tex]\(\text{H}_2\text{O}\)[/tex] (water).
- The remaining ions, [tex]\(\text{K}^+\)[/tex] from [tex]\(\text{KOH}\)[/tex] and [tex]\(\text{Br}^-\)[/tex] from [tex]\(\text{HBr}\)[/tex], combine to form potassium bromide ([tex]\(\text{KBr}\)[/tex]).
3. Write the complete balanced equation:
[tex]\[
\text{HBr} + \text{KOH} \rightarrow \text{H}_2\text{O} + \text{KBr}
\][/tex]
4. Choose the correct option:
- Option A (HBr): It cannot be missing because it is one of the reactants.
- Option B (BrOH): This species does not typically form in such a neutralization reaction.
- Option C (KOH): It also cannot be missing because it is the other reactant.
- Option D ([tex]\(\text{KBr}\)[/tex]): This is the salt that forms as a result of the reaction.
Thus, the missing element in the reaction is potassium bromide ([tex]\(\text{KBr}\)[/tex]).
Therefore, the correct answer is:
[tex]\[
\text{Option D: } KBr
\][/tex]
