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Why is DeltaH=DeltaU for the following t...

Why is `DeltaH=DeltaU` for the following two reactions? Explain.
(i) `NaOH(aq)+HCl (aq)toNaCl(aq)+H_(2)O(l)`
(ii) `CH_(4)(g)+2O_(2)(g) to CO_(2)(g)+2H_(2)O(g)`.

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(i) This reaction occurs in a solution. For a reaction occurring in a solution, `DeltaH=DeltaU`.
(ii) For this reaction `Deltan` (total number of moles of gaseous products-total number of moles of gaseous reactants)
`=(1+2)-(1+2)=0`. So, `DeltaH=DeltaU` according to the relation `DeltaH=DeltaU+DeltanRT`.
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