Question

Why can't we neutralise acid with strong alkali to neutralise come. Acid

Answer 1

The equation for any strong acid being neutralised by a strong alkali is essentially just a reaction between hydrogen ions and hydroxide ions to make water. ... If the reaction is the same in each case of a strong acid and a strong alkali, it isn't surprising that the enthalpy change is similar

Answer 2

enthalpy of neutralisation which states that “ IT IS THE CHANGE IN ENTHALPY WHEN ACID AND BASES REACTS TOGETHER AND FORMS 1 MOLE OF H2O “

STRONG ACIDS AND BASES do have this property of 100 % dissociation if dissolved in water .Let's try to understand it with an example

HCl + NaOH —-> Nacl + H2O This is the overall reaction equation

Cl- + Na+ ——-> NaCl

H+ + OH- ——-> H2O

Now if we notice the definition , we will find that it solely depends on formation of 1 mole of water , it does not involves what moles of salt are forming .

Eg.

1/2 H2SO4 + NaOH →1/2 Na2SO4 + H2O ✓✓✓✓✓✓

H2SO4 + 2 NaOH → Na2SO4 + 2H2O ×××××××××

Above first equation is perfectly balanced for depicting the neutralisation reaction .

Now coming back to answer part as why the enthaphy of neutralisation is constant ,it's because it solely count in the formation of 1 mole water irrespective of what kind of salt will be formed .