Effect on Enthelpy Changes By Using HNO3 Instead of HCl

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Using nitric acid (HNO3) instead of hydrochloric acid (HCl) in the reaction with sodium hydroxide (NaOH) can affect the measured enthalpy changes due to HNO3 being a weaker strong acid, which may not fully dissociate. This partial dissociation means that the enthalpy of the reaction involving HNO3 must account for the undissociated acid, potentially leading to a lower enthalpy change value compared to HCl. The net ionic equation for both reactions appears similar, suggesting minimal impact, but the difference in dissociation could be significant depending on experimental precision. While the effect may be small, it is not negligible and should be considered in precise measurements. Understanding these nuances is crucial for accurate thermodynamic assessments.
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Homework Statement


What effect, if any, would using nitric acid instead of hydrochloric acid in the reaction

NaOH(s) + HCl(aq) --> NaCl(aq) + H2O(l)

have on the enthalpy changes measured in an experiment?


Homework Equations



N/A

The Attempt at a Solution



I have no idea. Some experimental values I found online suggest that using nitric acid would give a lower enthalpy change value? But I wish to know the reasoning behind this.
 
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Consider the net ionic equation for both reactions.
 
Um after doing that i got the net reaction of
OH-(aq) + H+(aq) --> H2O(l)
for both reactions...so does that mean there is no effect?
 
ff_yy said:
does that mean there is no effect?

Yes.

With one important comment. HNO3 is the weakest of the so called strong acids, thus it is not necesarilly 100% dissociated (1% not dissociated in 0.1M solution). Thus enthalpy of the reaction between HNO3 and NaOH has to take HNO3 dissociation into account. No idea how large the difference is and how precise the experiment has to be for the difference to be measurable, but it exists.

But that's close to nitpicking.

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