The temperature of a 700. g bar of iron decreases by 30.(C when the iron is plunged into 500. g of water. What is the temperature increase of the water, assuming that no heat is lost in the transfer?

it is the most commonly accepted one

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.