When 150. ml of 0.400 m h+ are mixed with 200. ml of 0.500 m oh-, the final temperature of the solution is 26.5°c. what was the initial temperature of the solution before the reaction occurred? assume that the solution has a total mass of 350. g and a specific heat capacity of 4.184 j/g°c. the enthalpy of neutralization for the reaction is -62.0 kj/mol of water produced.

Explanation:

The reaction between hydrogen ion and hydroxide ion will be as follows.

so, ratio between hydrogen and hydroxide ions is 1 : 1.

Therefore, moles of = volume × concentration of

                             =

                              = 0.06 mol

Similarly, moles of = volume × concentration of

                               =

                              = 0.1 mol

Therefore, ratio of moles of hydrogen and hydroxide ions is as follows.

                                     0.06 : 0.1

                                  = 0.6 : 1

As, hydroxide ions are present in excess so, hydrogen ions are the limiting reagent.

Hence, moles of water formed = moles of ions = 0.06 mol.

So,    heat released = moles of

                                = 0.062 × 62.0 kJ/mol

                                = 3.72 kJ

                                = 3.72 × 1000 J

                                = 3720 J

Let T is the initial temperature. So,

              Heat released = Heat absorbed by the solution

                                       =

            3720 J =

                          T =

Thus, we can conclude that initial temperature is .                          

- lead + phosphoric acid = hydrogen + lead(ii) phosphate