Top answers

Molecules of hydrogen chloride, HCl, and molecules of fluorine, F2, contain the same number of electrons. Hydrogen chloride boils at –85 °C and fluorine boils at –188 °C.Explain why there is a difference in the boiling points of HCl and F2.

F2 has van der Waals’ forces, whilst HCl has permanent dipole–dipole attractions. Permanent dipole–dipole attractions are much stronger than induced dipoles. More enegery is required to break the stronger pe...
EA
Answered by Ellis A. • Chemistry tutor
31040 Views

Explain why benzene is colourless whereas azo dyes (such as methyl yellow) are coloured.

Azo dyes are coloured because they contain alternating single and double bonds, known as a conjugated system. This creates and areas of delocalisation above and below the plane of the molecule. This area of ...
AS
Answered by Amy S. • Chemistry tutor
44074 Views

How would you test for the presence of a phenol?

By adding Iron (III) Chloride to the solution and if it turns purple, it means a phenol is present.
RN
Answered by Rebecca N. • Chemistry tutor
10984 Views

What is the difference between pH and pKa?

pH is the measure of the concentration of proton in an aqueous environment, which is denoted as: pH = -log[H 3 O + ]. pKa however, is prefered when comparing how strong an acid is because it's the pH at whic...
AM
Answered by Anthony M. • Chemistry tutor
9292 Views

Why is phenol more reactive than benzene?

Benzene is made from an aromatic ring consisting of 6 carbon atoms and 6 hydrogen atoms, with delocalised electrons in the centre. Phenol has an additional hydroxy (-OH) group on the ring, and the oxygen ato...
EL
Answered by Erin L. • Chemistry tutor
6615 Views