Bases increase the concentration of hydronium ions by donating hydroxide ions to water molecules.
true
false

The given statement is false.

Explanation:

Acid as are defined as those substance which gives hydrogen ions in their aqueous solutions.

Base as are defined as those substance which gives hydroxide ions in their aqueous solutions.

The given statement is false.The correct statement is :

Bases increase the concentration of hydroxide ions by donating hydroxide ions to water molecules.

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