86.
there are many ionic compounds that dissolve in water to
a very small extent. one example is lead(ii) chloride. when
it dissolves an equilibrium is established between the solid
salt and its component ions. suppose you stir some solid
pbcl2 into water. explain how you would prove that the
compound dissolves but to a small extent? is the dissolving
process product-favored or reactant-favored?
pbcl2(s) 2 pb2+ (aq) + 2 cl-(aq)

the answer is d.) potassium

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