In article ,
says...
Perhaps we are confusing alkalinity with basic. Alkalinity is the measure of
a solution's ability to resist change in pH. Water which is measured "soft"
is typically lacking in carbonate ions. Those carbonates are a chief factor
in adding to a solution's "Alkalinity"

Alkaline is NOT a synonym for Basic. Basic is the opposite of Acidic.
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Water could very easily be soft and basic. Add NaOH to pure water and get a
very basic solution. It would however be very soft.


Well, that is the reverse of what I was taught in Chemistry, and rather
different from the definition in the Merriam-Webster Dictionary:

Main Entry: al·ka·line
Pronunciation: 'al-k&-l&n, -"lIn
Function: adjective
Date: 1677
: of, relating to, containing, or having the properties of an alkali or
alkali metal : BASIC; especially of a solution : having a pH of more than 7


and the Chemical meanings of BASIC:
Main Entry: 1ba·sic
Pronunciation: 'bA-sik also -zik
Function: adjective
Date: 1842
3 a : of, relating to, containing, or having the character of a chemical base
b : having an alkaline reaction
4 : containing relatively little silica basic rocks


whereas HARD, as in water, is:
Main Entry: 1hard
Pronunciation: 'härd
Function: adjective
Etymology: Middle English, from Old English heard; akin to Old High German
hart hard, Greek kratos strength
Date: before 12th century
2 b : characterized by the presence of salts (as of calcium or magnesium)
that prevent lathering with soap hard water