In: Chemistry
Why is the molar heat in a reaction between HCl and NaOH greater than in a reaction between HOAc and NaOH
HCl + NaOH -------> NaCl + H2O H = -57.3kj/mole
they are dissociate as
H++Cl- + Na++OH- -------> Na++Cl- + H2O H = -57.3kj/mole
net ionic equation
H+ + OH- ---------> H2O(l) H = -57.1kj/mole
Ethanlphy of strong acid and strong base is constant. Strong acid and strong base are completely ionisable.
CH3COOH + NaOH -------> CH3COONa + H2O
NaOH------> Na+ + OH-
acetic acid is weak acid it is incompletely dissociate.
CH3COOH <-------> CH3COO- + H+ equlibrium
completely dissociation of acetic acid some amount of energy is required.
The heat of energy of NaOH and CH3COOH is less than -57.3 kj/mole
The enthalphy of dissociation of acetic acid is 1.9kj/mole
CH3COOH + NaOH -------> CH3COONa + H2O H = -57.1-1.9 = 55.2 kj/mole