How to identify Parent topic in Keyword Research with FREE Tools?

Hi Guys,
I have been reading about LT kw's. Recently when I read an article (abt LT keywords) on ahref where it was mentioned some of LTKW's will be grouped under Parent topic by the google instead of ranking them as a separate LTKW (Topical kw as per ahref). In such case, how to find the Parent topic (without ahref tool)? Any free tools to find out? Pls help.

Thanks.

I don't think there's a free tool for that, but I wouldn't worry too much about it because Ahrefs' parent topics are not always accurate

Check what Google ranks for a keyword. That will give you the best idea.

Free tool will not do you any good. If you can't a paid tool like ahrefs, then you probably are not ready for this