ANS:B - exothermic

The catalytic ammonia synthesis reaction, as in the Haber process, is exothermic. In the Haber process, nitrogen gas (N2) and hydrogen gas (H2) are reacted over an iron catalyst under high pressure and temperature to produce ammonia gas (NH3) according to the following equation: N2(𝑔)+3H2(𝑔)⇌2NH3(𝑔)N2​(g)+3H2​(g)⇌2NH3​(g) This reaction releases heat energy as it proceeds in the forward direction, making it an exothermic reaction. The energy released helps to maintain the high temperature required for the reaction to occur efficiently. So, the correct answer is exothermic. An exothermic reaction is a type of chemical reaction that releases heat energy to its surroundings. In simpler terms, it's a reaction where the system loses heat to the surroundings during the process. This release of heat energy can manifest as an increase in temperature, warming the surroundings. Here are a few key points about exothermic reactions:

1. Energy Release: In an exothermic reaction, the energy released from the breaking and forming of chemical bonds is greater than the energy required to initiate the reaction. As a result, the excess energy is released as heat.
2. Temperature Change: Exothermic reactions typically result in an increase in temperature of the surrounding environment. This increase in temperature can sometimes be observed directly, such as feeling warmth when touching a container where an exothermic reaction is occurring.
3. Examples: Many combustion reactions, such as burning wood or fuel, are exothermic because they release heat energy as they occur. Other examples include neutralization reactions (e.g., the reaction between acids and bases), certain oxidation reactions, and the reaction in hand warmers or self-heating packs.
4. Energy Diagram: In an energy diagram for an exothermic reaction, the energy of the products is lower than the energy of the reactants. The difference in energy between the reactants and products represents the heat released during the reaction.