Given the reaction: 2Na(s) + 2H20(1) 2Na+(aq) + 2OH(aq) + H2(g) This reaction goes to completion because one of the products formed is
1.
an insoluble base
2.
a soluble base
3
a precipitate
4.
a gas

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

the answers are

c and c