Csharp # why char is using single quotes and string use 2?

Question

Csharp # why char is using single quotes and string use 2? can any one explain ., and what is bool double

Answer 1

string types are quotation marks to indicate more than one character, char is an apostrophe to indicate one character, to make code more readable.

As far as I know, bool double really shouldn't be a thing, (false.53) just doesn't seem right