The false statement among the following is (1) The heat...

The false statement among the following is (1) The heat liberated during the neutralization of $\mathrm{a}$ strong acid and a strong base in an aqueous solution is constant. (2) The heat of combustion is always an exothermic change. (3) The enthalpies of formation of organic substances can be conveniently determined from heat of combustion data. (4) Heat of fomation of a compound is equal in magnitude to heat of combustion.

The false statement among the following is
(1) The heat liberated during the neutralization of $\mathrm{a}$ strong acid and a strong base in an aqueous solution is constant.
(2) The heat of combustion is always an exothermic change.
(3) The enthalpies of formation of organic substances can be conveniently determined from heat of combustion data.
(4) Heat of fomation of a compound is equal in magnitude to heat of combustion.

Key Concepts

Hess's Law

Hess's Law states that the total enthalpy change for a chemical reaction is the same regardless of the pathway the reaction follows, because enthalpy is a state function. This principle allows for the calculation of reaction enthalpies by combining known values such as enthalpies of formation or combustion.

Neutralization Reaction

A neutralization reaction involves the chemical reaction between an acid and a base to form water and a salt. In aqueous solutions, this process typically releases a constant amount of heat when strong acids react with strong bases due to the consistent formation of water molecules.

Exothermic Reaction

An exothermic reaction is one that releases energy, usually in the form of heat, to its surroundings. This concept underpins many chemical processes such as combustion, where energy release is a defining characteristic.

Combustion Reaction

Combustion reactions involve the rapid oxidation of a substance, usually in the presence of oxygen, resulting in the production of heat and light. These reactions are inherently exothermic and their heat output, known as the heat of combustion, is a key factor in studying energy changes.

Enthalpy of Formation

The enthalpy of formation is the energy change that accompanies the formation of one mole of a compound from its constituent elements in their standard states. It is a fundamental concept in thermodynamics, providing insight into the stability and energy content of chemical compounds.

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