Which of the compounds above are strong enough acids to react almost completely with a hydroxide ion (pka of h2o = 15.74) or wit

Question

RSB [31]

3 years ago

8

Which of the compounds above are strong enough acids to react almost completely with a hydroxide ion (pka of h2o = 15.74) or wit

h a bicarbonate ion (pka of h2co3 = 6.37)?

Chemistry

2 answers:

prohojiy [21] · Answer 1 · 2022-06-19T21:22:45+03:00

Phenol, pentane-2,4-dione and diethyl malonate are strong enough to react completely with a hydroxide ion. But none of these compounds can react with a bicarbonate ion.

Further Explanation:

The formula to calculate ${\text{p}}{{\text{K}}_{\text{a}}}$ of acid is as follows:

${\text{p}}{{\text{K}}_{\text{a}}} = - \log {{\text{K}}_{\text{a}}}$ …… (1)

Here,

${{\text{K}}_{\text{a}}}$ is the dissociation constant of acid.

Equation (1) implies more the value of ${{\text{K}}_{\text{a}}}$ , smaller will be the ${\text{p}}{{\text{K}}_{\text{a}}}$ of the acid and vice-versa. The higher value of ${{\text{K}}_{\text{a}}}$ means the acid is completely dissociated into its respective ions when dissolved in the solvent and vice-versa. The compounds that have ${\text{p}}{{\text{K}}_{\text{a}}}$ values less than that of the given solvent will dissociate in it and thereby reacting with it and vice-versa.

The value of ${\text{p}}{{\text{K}}_{\text{a}}}$ of water is 15.74. The value of ${\text{p}}{{\text{K}}_{\text{a}}}$ of phenol is 9.89. The value of ${\text{p}}{{\text{K}}_{\text{a}}}$ of pentane-2,4-dione is 9. The value of ${\text{p}}{{\text{K}}_{\text{a}}}$ of diethyl malonate is 13.

All these compounds have ${\text{p}}{{\text{K}}_{\text{a}}}$ values less than that of water so these can react with hydroxide ion completely. But the value of ${\text{p}}{{\text{K}}_{\text{a}}}$ of ${{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ is 6.37. All the given compounds have ${\text{p}}{{\text{K}}_{\text{a}}}$ values greater than that of ${{\text{H}}_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ so these cannot react with a bicarbonate ion.

Learn more:

Write the chemical equation responsible for pH of buffer containing and : brainly.com/question/8851686
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Answer details:

Grade: High School

Chapter: Acid, base and salts

Subject: Chemistry

Keywords: Ka, pKa, acids, phenol, pentane-2,4-dione, diethyl malonate, 13, 15.74, 6.37, 9, 9.89, H2CO3, bicarbonate ion, water, value, hydroxide ion, compounds.

luda_lava [24] · Answer 2 · 2022-06-19T19:05:45+03:00

The compounds can react with OH⁻ and HCO₃⁻ only C₅H₆N pyridinium

<h3><em>Further explanation </em></h3>

In an acid-base reaction, it can be determined whether or not a reaction occurs by knowing the value of pKa or Ka from acid and conjugate acid (acid from the reaction)

Acids and bases according to Bronsted-Lowry

Acid = donor (donor) proton (H + ion)

Base = proton (receiver) acceptor (H + ion)

If the acid gives (H +), then the remaining acid is a conjugate base because it accepts protons. Conversely, if a base receives (H +), then the base formed can release protons and is called the conjugate acid from the original base.

From this, it can be seen whether the acid in the product can give its proton to a base (or acid which has a lower Ka value) so that the reaction can go to the right to produce the product.

The step that needs to be done is to know the pKa value of the two acids (one on the left side and one on the right side of the arrow), then just determine the value of the equilibrium constant

Can be formulated:

K acid-base reaction = Ka acid on the left : K acid on the right.

or:

pK = acid pKa on the left - pKa acid on the right

K = equilibrium constant for acid-base reactions

pK = -log K;

$K~=~10^{-pK}$