Chemistry Thermochemistry BUMHS 2024
PMDC Verified Question 19 of 81
The change in enthalpy for the reaction:
$$ NaOH_{(aq)} + HNO_{3(aq)} \rightarrow NaNO_{3(aq)} + H_2O_{(l)} $$
A
Heat of decomposition
B
Heat of formation
C
Heat neutralization
D
Heat of combustion
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Heat neutralization
Concept:

Thermochemical reaction names strictly follow the nature of the reactants interacting.

Formula:

$$ \text{Strong Base} + \text{Strong Acid} \rightarrow \text{Aqueous Salt} + H_2O_{(l)} $$

Solution:

  • \( NaOH \) is a strong base, and \( HNO_3 \) is a strong nitric acid.


  • They undergo a classic double displacement reaction where the \( H^+ \) and \( OH^- \) ions combine to form water.


  • The specific enthalpy change (\( -57.4 \text{ kJ/mol} \)) associated with the formation of 1 mole of water via an acid and base is formally defined as Heat of neutralization.


Why other options are incorrect:

It is not combustion (requires \( O_2 \)). It is not formation (which requires elemental reactants like solid Na and gaseous \( N_2/O_2 \)). It is not decomposition (which requires a single reactant breaking down).

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