Which statement is true about a basic solution?
its ph is equal to 7.
its ph is less than 7.
it has the same concentration of hydronium and hydroxide ions.
it has a greater concentration of hydroxide ion than hydronium ions.

It has the same concentration of hydronium and hydroxide ions.

Explanation:

the correct answer to this question is 2

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