A solution is known to contain either Ni2 or Cr3 . Addition of what single (1 only) reagent would identify which ion is present?

Explanation:

From the periodic table; both elements given are from the same group 3.

To test for which ion will be present in the experiment;

We added 6M aqueous sodium hydroxide  in excess.

This process is followed by the addition of hydrogen peroxide H2O2 while stirring.

Heat is then applied to the solution.

After we've carried out those process;

We will notice the following;

If is present, then a green  precipitate will be formed

If is present,then a yellow-colored will be formed.

answer; i believe that the correct answer is (a) potassium(k)

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.