How much arsenic does it take to kill a rat

The average estimated fatal dose of arsenic trioxide for humans is 125 mg. For a 70-kg man, this is equivalent to about 1.4 mg of arsenic per kilogram of body weight.

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.