You will complete the following equations on acid-base reactions. 1. Nitric acid + calcium hydroxide →
2. Phosphoric acid + iron (III) hydroxide →
3. Hydrochloric acid + lead (11) hydroxide →
4. Hydrochloric acid + sodium hydroxide →
You will use the steps below:
• write the formulas for the acids and bases
• complete the reaction by predicting the products
• balance the equation
name the products.

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