Which statement best helps to explain the observation that NH3(1) boils at -28°C, whereas PH: (1) boils at -126°C? A
The dispersion forces in NH3 are weaker than the dispersion forces in PH3.
B
The dispersion forces in NH3 are stronger than the dipole-dipole forces in PHz.
С
NH3 has hydrogen bonding that is stronger than the dipole-dipole forces in PH3
D
NH3 has hydrogen bonding that is weaker than the dipole-dipole forces in PH3.

C.

Explanation:

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