Consider this reaction: $KOH + HBr \rightarrow KBr + H _2 O$
Which is the base in this reaction?
A. KOH
B. HBr
C. KBr
D. $H _2 O$
Answer (2)
Identify the base as a substance that accepts protons.
Recognize KOH as a strong base that dissociates into O H − ions, which accept protons.
HBr is an acid, KBr is a salt, and H 2 O is water.
Conclude that the base in the reaction is K O H .
Explanation
Identifying the Problem We are given the reaction: K O H + H B r → K B r + H 2 O . We need to identify the base in this reaction from the given options: KOH, HBr, KBr, and H 2 O .
Understanding Bases A base is a substance that can accept a proton ( H + ). In this reaction, potassium hydroxide (KOH) reacts with hydrobromic acid (HBr) to form potassium bromide (KBr) and water ( H 2 O ).
Analyzing the Reaction KOH is a strong base because it dissociates in water to produce hydroxide ions ( O H − ), which can accept protons. HBr is a strong acid that donates protons. KBr is a salt formed from the reaction, and H 2 O is water.
Conclusion Therefore, the base in this reaction is KOH.
Examples
In everyday life, understanding bases is crucial in various applications. For example, antacids contain bases like magnesium hydroxide ( M g ( O H ) 2 ) or aluminum hydroxide ( A l ( O H ) 3 ) to neutralize excess stomach acid (hydrochloric acid, HCl), providing relief from heartburn. Similarly, soaps and detergents contain bases that help to emulsify fats and oils, making them soluble in water for effective cleaning. The reaction between an acid and a base is a fundamental concept in chemistry with widespread practical applications.
In the reaction K O H + H B r → K B r + H 2 O , the base is KOH, which is a strong base that accepts protons. Thus, the correct answer is option A: KOH. This reaction demonstrates a typical acid-base interaction where KOH neutralizes HBr.
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