Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The enthalpy of any strong acid by a strong base is practically the same ($-13.7~kCal~mol^{-1}$). Reason (R): Every neutralization reaction involves the combination of $H^{+}$ and $OH^{-}$ ions to form water.}

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

$-13.7~kCal$ or $-57.3~kJ$: It's the "tax" paid to form one mole of water!

Answer 1

The Correct Option is A

Step 1: Concept Neutralization is the reaction between an acid and a base.

Step 2: Meaning Strong acids and strong bases dissociate completely in aqueous solution.

Step 3: Analysis The net ionic equation for any strong acid-strong base reaction is simply $H^{+} + OH^{-} \rightarrow H_{2}O$. Since the reactants are effectively the same in every case, the heat released per mole of water formed is constant.

Step 4: Conclusion The constant value of enthalpy is a direct result of the uniform ionic process described in the reason. Final Answer: (A)