Why at room temperature is H2O a liquid, but H2S is a gas?

This question is basically just asking you why water has a higher boiling point that H2S. So you need to ask yourself what is the factor which means water has a higher boiling point? If you remember back to electronegativies of the elements in the periodic table, you may recall that the elements in the top right hand corner are the most electronegitive (i.e. they pull electron density towards them). Oxygen sits above sulfur in row 6 of the periodic table and so is more electronegative. Furthermore, you may also recall that F, N and O are the three most electronegative atoms in the table. This property means that when they are attached to a hydrogen (which has a much lower electronegativity) there is a difference in electronegativity. This different is particularly large for H-F, H-N and H-O, resulting in a special intermolecular interaction called hydrogen bonding which is exclusive to these bonds. Therefore, H2O has a higher boiling point than H2S because H2O has the ability to hydrogen bond whereas H2S does not. Hydrogen bonds are stronger than other intermolecular interactions such as van der Waals interactions or dipole-dipole interations, so require more energy to break them. Hence, water has a higher boiling point (or is a liquid at room temperature) whereas H2S is a gas at room temperature.

MK
Answered by Melissa K. Chemistry tutor

38893 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

Explain the trend in first ionisation energies across a period.


1.5 g of hydrocarbon undergoes complete combustion to give 4.4 g of CO2 and 2.7 g of H2O. Given this data, what is the empirical formula of this hydrocarbon?


For the reaction 2H2 + O2 -- 2H2O, how do I give an equation for the equilibrium constant in terms of the concentrations of products and reactants involved?


Please can you explain E/Z isomers?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences