Which of the following is an exchange reaction? a. HCl + NaOH NaCl + H₂O b. dehydration c. C₆H₁₂O₆+C₆H₁₂O₆→C₁₂H₂₄0₁₂ d. hydrolysis
The Correct Answer and Explanation is :
The correct answer is a. HCl + NaOH → NaCl + H₂O.
Explanation:
An exchange reaction, also known as a double displacement reaction, involves the exchange of components between two compounds, typically forming a precipitate, gas, or water. In this case, hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH) to form sodium chloride (NaCl) and water (H₂O), which is a typical example of an exchange reaction. The general form of an exchange reaction is:
[ AB + CD \rightarrow AD + CB ]
In this reaction:
- HCl dissociates into H⁺ and Cl⁻ ions.
- NaOH dissociates into Na⁺ and OH⁻ ions.
- The H⁺ from HCl combines with the OH⁻ from NaOH to form water (H₂O), while Na⁺ from NaOH combines with Cl⁻ from HCl to form NaCl.
Thus, both positive and negative ions are exchanged between the two reactants.
Breakdown of the Other Options:
- b. Dehydration: A dehydration reaction is a type of chemical reaction in which water is removed from a molecule, usually to form a more complex compound. This is not an exchange reaction, but rather a specific type of condensation reaction. For example, the formation of an ester from an alcohol and an acid through the removal of water.
- c. C₆H₁₂O₆ + C₆H₁₂O₆ → C₁₂H₂₄O₁₂: This is a condensation reaction, specifically a synthesis reaction, where two molecules (glucose in this case) combine to form a larger molecule, maltose, with the release of water. It’s not an exchange reaction since there is no swapping of ions or components between separate reactants.
- d. Hydrolysis: A hydrolysis reaction involves the breakdown of a compound by water. Water is added to break bonds, which is the opposite of a dehydration reaction. It doesn’t involve an exchange of ions but rather the addition of water to a compound.
In summary, option a (HCl + NaOH → NaCl + H₂O) is the correct answer because it is an exchange reaction, where the ions of the two reactants are exchanged to form new products.