A student titrated a solution containing 0.3706 g of an unknown triprotic acid to the endpoint using 28.94 mL of a 0.3021 M KOH solution. What is the molar mass of the unknown acid

particle   p is an electron and particle q is a neutron

what are the statements

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