Question

Is negative delta H exothermic?

Answer 1

Hint :The value of delta H ( $\mathrm{\Delta }H$ ) is not determined by the surroundings, but by the system itself. Exothermic is a reaction in which heat is released in the surroundings and endothermic is a reaction in which heat is absorbed from the surroundings. Thus, the value of\ Delta H ( $\mathrm{\Delta }H$ ) will be opposite with one another.

Complete Step By Step Answer:
The correct answer to this question is yes, negative delta H ( $-\mathrm{\Delta }H$ ) represents an exothermic reaction. On the contrary, the positive value of delta H ( $+\mathrm{\Delta }H$ ) will represent an endothermic reaction.
An exothermic reaction is a reaction in which heat is evolved at the end of the reaction by the products. Exothermic reactions do not require any kind of energy to take place.
An endothermic reaction is a reaction in which heat is absorbed at the start of the reaction by the reactants. Endothermic reactions require some form of energy from the surrounding to take place.
The change in enthalpy, which is delta H ( $\mathrm{\Delta }H$ ), depends only on the system in which the reaction is taking place and not on the surroundings.
The value of change in enthalpy, which is delta H ( $\mathrm{\Delta }H$ ), is negative for exothermic reactions as the enthalpy of products is less than the enthalpy of reactants. As the enthalpy of products is less than that of reactants, excess heat will be released at the end of the reaction.
On the contrary, the change in enthalpy of endothermic reactions will be positive as the enthalpy of products will be more than that of the reactants. As the enthalpy of reactants is less than the products, the reactants will require some additional form of energy to convert into products.
Therefore, change in enthalpy, which is delta H ( $\mathrm{\Delta }H$ ), will be negative for exothermic reactions.

Note :
We can say that the change in enthalpy of a reaction is directly proportional to change in heat. If the enthalpy of products is more than that of reactants, heat of products will also be more than that of reactants and thus excess of heat will be released when products are formed. Same thing happens for endothermic reactions, but in them heat has to be supplied to the reactants.