Answer:
[HF]₀ = 0.125M
Explanation:
NaOH + HF => NaF + H₂O
Adding 20ml of 0.200M NaOH into 25ml of HF solution neutralizes 0.004 mole of HF leaving 0.004 mole NaF in 0.045L with 0.001M H⁺ at pH = 3. This is 0.089M NaF and 0.001M HF remaining.
=> 45ml of solution with pH = 3 and contains 0.089M NaF from titration becomes a common ion problem.
HF ⇄ H⁺ + F⁻
C(eq) [HF] 10⁻³M 0.089M (<= soln after adding 20ml 0.200M NaOH)
Ka = [H⁺][F⁻]/[HF]₀ => [HF]₀ = [H⁺][F⁻]/Ka
[HF]₀ = (0.001)(0.089)/(7.1 x 10⁻⁴) M = 0.125M
Should be , b
. Not positive tho
Answer:
B. CH3Br
Explanation:
Dipole -Dipole interactions take place in polar molecules.
CH3Br exhibits dipole -dipole forces as its strongest attraction between molecules because it is a polar molecule due to the slightly negative dipole present on the Br molecule.
While O2 is a nonpolar molecule due to its linear structure, CCl4 has zero resultant dipole moment, Helium is non-polar and BrCH2CH2OH is a non polar compound having net dipole moment is zero.
Hence, the correct option is B. CH3Br.
Active metals are those metals in the group 1 of the periodic table.
Electronegativity is the trend to atract electrons.
Active metals have few valence electron, because their last shell is of the kind ns^1 or ns^2
Then, these atoms do not trend to attract electrons. The most electronegative atomos are those who have 7 valence elecfrons; this is their last shell is of the kind ns^7, because when they attract one electron to its valence shell they will complete 8 electrons which is the most stable configuration.
The correct answer would be the first one. The reaction that will not conduct electricity would be CH3OH(l) = CH3OH(aq) since it stays as a single molecule in solution. It does not have any free electrons that will allow the flow of current into the solution. Other options dissociates into ions which has free electrons so they allow current to flow.
