Which of the following is an acid-base reaction?
[tex]Fe ( s )+2 AgNO _3( aq ) \rightarrow 2 Ag ( s )+ Fe \left( NO _3\right)_2( aq )[/tex]
[tex]C ( s )+ O _2(g) \rightarrow CO _2(g)[/tex]
[tex]MgSO _4( aq )+ Ba \left( NO _3\right)_2( aq ) \rightarrow Mg \left( NO _3\right)_2( aq )+ BaSO _4(s)[/tex]
[tex]2 HClO _4( aq )+ Ca ( OH )_2( aq ) \rightarrow 2 H _2 O ( I )+ Ca \left( ClO _4\right)_2( aq )[/tex]
None of the above are acid base reactions.
Answer (2)
The fourth reaction, 2 H Cl O 4 ( a q ) + C a ( O H ) 2 ( a q ) → 2 H 2 O ( I ) + C a ( Cl O 4 ) 2 ( a q ) , is an acid-base reaction, as it involves the transfer of protons between the acid and the base. The other reactions do not fit this definition. Therefore, the correct answer is the fourth option.
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Identify acid-base reactions as involving proton ( H + ) or hydroxide ion ( O H − ) transfer.
Analyze each reaction to determine if it fits the definition of an acid-base reaction.
Recognize that the fourth reaction, 2 H Cl O 4 ( a q ) + C a ( O H ) 2 ( a q ) → 2 H 2 O ( I ) + C a ( Cl O 4 ) 2 ( a q ) , is a neutralization reaction.
Conclude that the fourth reaction is the acid-base reaction: 2 H Cl O 4 ( a q ) + C a ( O H ) 2 ( a q ) → 2 H 2 O ( I ) + C a ( Cl O 4 ) 2 ( a q )
Explanation
Identifying Acid-Base Reactions We are asked to identify an acid-base reaction from a list of chemical reactions. An acid-base reaction involves the transfer of protons ( H + ) or hydroxide ions ( O H − ). Let's examine each reaction.
Analyzing Each Reaction
F e ( s ) + 2 A g N O 3 ( a q ) → 2 A g ( s ) + F e ( N O 3 ) 2 ( a q ) : This is a redox reaction, not an acid-base reaction.
C ( s ) + O 2 ( g ) → C O 2 ( g ) : This is a combustion reaction, not an acid-base reaction.
M g S O 4 ( a q ) + B a ( N O 3 ) 2 ( a q ) → M g ( N O 3 ) 2 ( a q ) + B a S O 4 ( s ) : This is a precipitation reaction, not an acid-base reaction.
2 H Cl O 4 ( a q ) + C a ( O H ) 2 ( a q ) → 2 H 2 O ( I ) + C a ( Cl O 4 ) 2 ( a q ) : This reaction involves an acid ( H Cl O 4 ) and a base ( C a ( O H ) 2 ) reacting to form water and a salt. This is a neutralization reaction, which is a type of acid-base reaction.
Conclusion The fourth reaction is an acid-base reaction.
Examples
Acid-base reactions are fundamental in many areas of chemistry and everyday life. For example, the reaction between stomach acid (hydrochloric acid, H Cl ) and an antacid (like calcium carbonate, C a C O 3 ) is an acid-base reaction that neutralizes the acid and relieves heartburn. Similarly, in agriculture, farmers use lime (calcium hydroxide, C a ( O H ) 2 ) to neutralize acidic soils, making them more suitable for growing crops. These reactions involve the transfer of protons or hydroxide ions, leading to the formation of water and a salt.
