Answer:
This question appears incomplete
Explanation:
This question appears incomplete because of the absence of options. However, hydrogen is placed in group 1 because it has just one electron in it's outermost shell (which happens to be the only shell it has) just like every other group 1A/group 1 element. While helium is placed in group 8A/group 18 because it has a completely filled outermost shell (which is also the only shell it has) just like every other element in group 8A/group 18.
C is wrong, the real answer is B: to add tartness, and the reason why is because citric acid comes from jam, jellies, and more! And that is why the answer B is the correct answer.
Hope this helped!
Nate
(P.S. if you buy jams and real the ingredients, it will say "citric acid." :))
The unit for speed is usually m/s
The answer I got is 151. 5 K. I hope that helps.