Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and for the reaction comes out to be positive. The energy is absorbed and hence the temperature of the surroundings decrease.
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and for the reaction comes out to be negative. The energy is released and hence the temperature of the surroundings increase.
Thus with enthalpy change of , the tempearture increase.
I think it's Sodium Sulfide, because Na2S contains one Sodium and two Sulfur. Plus Sulfide<span> is used to describe any of three types of chemical compounds that contain sulfur.</span>