Answer:
b. electronegativity
Explanation:
The ability of an atom in a molecule to attract electrons is best quantified by the _Electronegativity_.
Electronegativity is the ability of an atom to attract a shared pair of electron which is loosely held. Polar molecules often possess such properties. The Halogen group (group 17) is famous for such property because it has the highest electronegativity in periodic table.
We know that molarity = mol/L, so:
1.5 M = x mol/0.345 L
1.5 M * 0.345 L = x mol => 0.5175 mol
0.5175 mol/0.250 L = 2.07 M
Your new molarity of the solution will be 2.07 M.