The concentration of hydroxide ions is greater than the concentration of hydronium ions for acidic solutions.

True
False

True

Explanation:

It's true because the pH is a measure of how basic or acid a solution is. In an acidic medium, the pH scales goes from 0 to 7. While in a basic medium goes from 7 to 14. The lower the pH value of the most acid the solution is.

1. The expression pH = -log(molar concentration of hydronium) allow to calculate the pH of a solution.

2. On the other hand, the expression pOH = -log(molar concentration of hydroxide) allow to determine the pOH of a solution.

The values of pH and pOH always obey the following expression:

pH + pOH = 14

Thus if for instance the pH becomes smaller the pOH must become bigger in order to fulfill the equation. Which means that the concentration of hydronium ions is greater than the hydroxide concentration.

For example, in an acidic medium:

if pH= 3, pOH= 11

In this case the molar concentration of hydronium is 0,001M. And the molar concentration of hydroxide ions is just 0,00000000001M.

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