Answer: option C. HF
Explanation: A polar bond is a covalent bond between two atoms where the electrons forming the bond are unequally distributed. Fluorine is more electronegative than hydrogen so the electrons in the bond are more closely associated with the fluorine atom than with the hydrogen atom.
Answer: The particles in a solid are packed very close to each other.
The half life for C14 is 5730 years.
We assume that Carbon 14/ Carbon 12 ratio was steady for living organisms over time, the problem is actually telling us that

= 0.0725 =

ˣ
Take the natural logarithm and In on both sides.
ln(0.725) = ln

ˣ
= - 0.3216 = xln (

= -0.6931x.
So x = (-.3216) / (-0.6931) = 0.464
or
t/t₁/₂ = 0.464
So t = 0.464 x t₁/₂ = 0.464 * 5730 yrs = 2660 years.
Psolution = X · PH_20
= 0.966 · 31.8 torr
= 30.7 torr
H is 4*10^6 M , OH is 2.5*10^-9 M