Why "as to" is followed by "whether" and not by a noun in the following sentence?
Why "as to" is followed by "whether" and not by a noun in the following sentence? As far as I know, prepositions should be followed by nouns. I have also seen "as to" followed by "how", "which", "when" and others.

Sentence: There is some doubt as to whether the information is totally accurate.

Question

Why "as to" is followed by "whether" and not by a noun in the following sentence?
Why "as to" is followed by "whether" and not by a noun in the following sentence? As far as I know, prepositions should be followed by nouns. I have also seen "as to" followed by "how", "which", "when" and others.

Sentence: There is some doubt as to whether the information is totally accurate.

Answer

prepositions are not always followed by nouns.

Answer

The sentence has the same meaning if you replace "as to" with "regarding" or "concerning."  You can also delete "as to" and, at least in U.S. English, the meaning will not change.  Does that help?