When comparing h2, nh3, o2, and ch4, which of the following statements is correct? a. ch4 has the highest boiling point because it experiences dipole-dipole forces. b. h2 has the strongest intermolecular forces because it has the lowest mass. c. nh3 has the highest boiling point because it experiences hydrogen bonding. d. o2 has the strongest intermolecular force because it experiences london dispersion forces.

c. NH3 has the highest boiling point because it experiences hydrogen bonding.

Explanation:

NH3 has three N-H polar covalent bonds with N and H having partial negative and positive charges respectively. The partial negative dipole of N from one NH3 molecule forms a hydrogen bond with the partial positive dipole of H from one NH3 molecule.  

δ- δ+   δ- δ+

N-H...N-H

Thus NH3 experiences hydrogen bonding and has the highest boiling point.  

The C-H bond in CH4 is nonpolar. Dipoles exist in polar covalent bonds. Hence option A is incorrect.  

Higher the molecular mass the greater is the intermocleuclar force of attraction. Hence option C is incorrect.  

London dispersion forces are weaker intermolecular forces than hydrogen bonding. Hence option D is incorrect.  

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.