Name the complex mncl2(en)2. the oxidation number of manganese is +2.

The name  of  MnCl2(en)2  is    (II)  ion
when  naming  a  complex  compound  the  ligand  are  named   before   the  metal  ion.  Since  chlorine  is  a  negative  ligand  its  name  end  with O  that  is  chloro.
Bis  is  used  in   front  of  ethylenediamine  since  it  they  are  two  and  it  is  a  more  complicated  ligand

Solubility = [SO₄²⁻]

Explanation:

Solubility of Ag₂SO₄ can be understood seen its Ksp equilibrium:

Ag₂SO₄(s) ⇄ SO₄²⁻ + 2Ag⁺

Where 1 mole of silver sulfate dissolves producing 1 mole of sulfate ion and 2 moles of silver ion.

Solubility is defined as: "the amount of solid that can be dissolved per liter of solution".

In the dissolution process, the moles of Ag₂SO₄ dissolved are equal to moles of SO₄²⁻.

That means:

Solubility = [SO₄²⁻]