On the basis of the reactions observed in the six test tubes, explain why the position of hydrogen cannot be fixed exactly with respect to all of the other elements listed in the activity series in g

Explanation :

Hydrogen is first atom of periodic table and has only one electron in its orbital.

It can released its single electron easily and exist as ion as well as it can easily accepts an electron to complete its octet and exist as therefore it placed in group-1 (alkali metals) as well as group-17 (halogens).

Conclustion:

It can easily released electron and accepts electron therefore its position is not fixed with respect to other elements.

that's what i got you can count the number of atoms