The same thing would work with that turkey baster as long as you could get the boiling water out to where you needed it while it was still that hot without burning your self in the process. Lugging boiling water anywhere, in anything, can be extremely hazardous to you.

A turkey baster is not the right tool for this job. What about a tea kettle? Or a large sauce pan filled half way with water?

Why don't you buy one of those notched dandelion weeders and dig it out? The only place I would use boiling water to kill weeds is in the cracks of pavement where other plants would not be harmed.

I recall a former neighbour who put some RoundUp in a spray bottle and sprayed all the dandelions on her lawn with it, and then wondered why she had a polka dot lawn...