Acup of water plugged by a brown cork is insulated by a second styrofoam cup. a black rod and a thermometer are inserted through the cork into the water. the thermometer is a, the water is b, the outer cup is c.
this part insulates the reaction chamber from the transfer

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

a corroding iron, if that's one of your choices