What is the percent ionization in a 0.580 M solution of formic acid ( HCOOH) (Ka=1.78*10^-4)?

% α = 1.7243 %

Explanation:

∴ Ka = 1.78 E-4 = [H+][COOH-]/[HCOOH]

∴ α = [COOH-] / [COOH-] + [HCOOH]

∴ C HCOOH = 0.580 M

mass balance:

⇒ C HCOOH = 0.580 = [HCOOH] + [COOH-]

charge balance:

⇒ [H+] = [COOH-]

Replacing:

⇒ Ka = 1.78 E-4 = [H+]²/(0.580 - [H+])

⇒ [H+]² + 1.78 E-4[H+] - 1.0324 E-4 = 0

⇒ {H+] = 0.01 M

⇒ [COOH-] = 0.01 M

⇒ [HCOOH] = 0.580 - 0.01 = 0.5699 M

⇒ α = (0.01)/(0.01 + 0.5699) = 0.0172

⇒ % α = 1.7243 %

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.