D it’s quartz on the Mohs scale thing it’s ranked 7
Explanation:
Let us assume that total mass of the solution is 100 g. And, as it is given that acetic acid solution is 12% by mass which means that mass of acetic acid is 12 g and 88 g is the water.
Now, calculate the number of moles of acetic acid as its molar mass is 60 g/mol.
No. of moles =
= 
= 0.2 mol
Molarity of acetic acid is calculated as follows.
Density = 
1 g/ml = 
volume = 100 ml
Hence, molarity = 
= 
= 2 mol/l
As reaction equation for the given reaction is as follows.

So, moles of NaOH = moles of acetic acid
Let us suppose that moles of NaOH are "x".
(as 1 L = 1000 ml)
x = 20 L
Thus, we can conclude that volume of NaOH required is 20 ml.
Answer is: Ksp for calcium sulfate is 2.36·10⁻⁴.
Balanced chemical reaction (dissociation):
CaSO₄(s) → Ba²⁺(aq) + SO₄²⁻(aq).
m(CaSO₄) = 0.209 g.
n(CaSO₄) = m(CaSO₄) ÷ M(CaSO₄).
n(CaSO₄) = 0.209 g ÷ 136.14 g/mol.
n(CaSO₄) = 0.00153 mol.
s(CaSO₄) = n(CaSO₄) ÷ V(CaSO₄).
s(CaSO₄) = 0.00153 mol ÷ 0.1 L = 0.0153 M.
Ksp = [Ca²⁺] · [SO₄²⁻].
[Ca²⁺] = [SO₄²⁻] = s(CaSO₄).
Ksp = (0.0153 M)² = 2.36·10⁻⁴.