[Meter]

How exactly do you quantify the strength of Lewis acids and bases? For Brønsted-Lowry acids/bases we can quantify their strength using pKa values. What about pH? For example, if I made a solution of AlCl₃, would I get a reading on normal pH paper?

Surprisingly, this was not covered at all in our gen chem course.

[Orcio_87]

There is no universal scale to compare strength of Lewis acid / base.

One base can form stronger bond with C(CH₃)₃⁺ and weaker with CH₃+, other - in reverse. All depends on what compound is chosen.

Similiar - in nature - some elements (metals) are more attracted to oxygen, other to sulfur. So - they acidicity will depend whether it is measured towards O or S.

[Meter]

Thanks. Is this data well defined? Like strength with relation to oxygen, suflur, etc.?

[Orcio_87]

All scales are based on the reaction constant and presented in normal ("K") or logarythmic ("pK") scale.