Quick!
a solution at 25 degrees celsius has a poh of 6.42. what is the ph of this solution?

0.842
3.80
5.59
7.58

Answer : The correct option is, 7.58

Explanation : Given,

pOH = 6.42

pH : It is defined as the negative logarithm of the hydrogen ion concentration.

As we know that,

Now put the value of pOH in this expression, we get the pH of this solution.

Therefore, the pH of this solution is, 7.58

the dependant variable is spilled water

the independent is the heat

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