Consider titration of 100.0 mL of 0.100 M H2NNH2 (Kb = 3.0x10^-6) by 0.200 M HNO3. Calculate the pH of the resulting solution after the following volumes of HNO3 have been added.

0.0 mL

20.0 mL

25.0 mL

40.0 mL

50.0 mL

so she was walking and she stepped on warm jeffy , uh uh uhh dadye i just pooped my pants

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol