How many milliliters of a 0.150 M NaOH solution must be added to a 25.0-mL sample of 0.150 M butanoic acid, CH3(CH2)2CO2H, in order to create a buffer with a pH of 4.82? Ka of butanoic acid = 1.5 x 10-5

12.5 mL of NaOH

Explanation:

0.150 M NaOH

CH3-CH2-CH2-COOH  0.150M

This is the data given. The reaction of both reactants make a neutralization and a salt

CH3-CH2-CH2-COOH  +  NaOH →  NaCH3-CH2-CH2-COO  +  H₂O

As both compounds produce a buffer, we can apply the Henderson Hasselbach equation:

pH = pKa + log ( mmol NaOH / Initial mmol of acid - mmol NaOH)

Final mmol of acid = mmol of NaOH

Final mmol of acid = Initial mmol of acid - mmol of NaOH we added.

Let's find the data to replace in the formula:

pKa butanoic acid = -  log Ka → - log 1.5×10⁻⁵  = 4.82

Initial mmol of acid = M . mL → 25 mL . 0.150M → 3.75 mmol

Notice that M = mmol/mL → mmol = M . mL.

We replace → 4.82 = 4.82 + log mmol NaOH / ( 3.75 mmol - mmol NaOH)

As pH = pKa, notice that log = 1 so:

mmol NaOH / ( 3.75 mmol - mmol NaOH) = 1

mmol NaOH = 3.75 mmol - mmol NaOH

2mmol NaOH = 3.75 → mmol NaOH = 3.75 / 2 = 1.875

M = mmol /mL → mL = mmol / M → 1.875 mmol / 0.150M = 12.5 mL

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.

the answer is 1260

you spend 7 hours in school for 1 school day with 5 school days in 1 school week with 36 school weeks in a school year.

7*5*36= 1260 it's all about multiplying