Neutralization reactions are generally exothermic and thus ΔH is negative. Heat measurements are performed by carrying out the reaction in a special container called a calorimeter. The heat (Q) given off by the neutralization reaction is absorbed by the reaction solution and the calorimeter.

Why is heat released in a neutralization reaction?

SInce strong acids and strong bases are completely dissociated in solution, no formal bonds are being broken. The formation of two very strong covalent bonds between hydrogen and the hydroxide ion is responsible for the neutralization reaction's exothermic character.

Does neutralisation give out heat?

Enthalpy changes of neutralisation are always negative - heat is given out when an acid and and alkali react. For reactions involving strong acids and alkalis, the values are always very closely similar, with values between -57 and -58 kJ mol^-1.