The amount of K₂SO₄ (in gms) present in dissolved state of 100ml of solution whose K⁺ concentration is 0.075M

The molar mass of K₂SO₄ = 174 g

Volume of solution = 100 ml = 0.1 L

K₂SO₄ will break into 2 K⁺  and SO₄^-2 ions

Conc of K⁺ = 0.075 M

Conc. of K₂SO₄ $=\frac{0.075}{2}=0.0375 \mathrm{M}$

Moles of K₂SO₄ = conc. of K₂SO₄ $\times$volume of solution

 $=0.0375\times 0.1=0.00375$

$\mathrm{moles}=\frac{\mathrm{wt}. \mathrm{of} {\mathrm{K}}_2{\mathrm{SO}}_4}{\mathrm{Molar} \mathrm{mass} \mathrm{of} {\mathrm{K}}_2{\mathrm{SO}}_4}$

$\mathrm{wt}. \mathrm{of} {\mathrm{K}}_2{\mathrm{SO}}_{4 }= \mathrm{moles}\times \mathrm{molar} \mathrm{mass}$

$=0.00375\times 174=0.6525\approx 0.65 \mathrm{gms}$

Therefore, the required answer is A) 0.65.