# 14.1 Brønsted-lowry acids and bases  (Page 4/14)

 Page 4 / 14
${\text{2H}}_{2}\text{O(}l\right)\phantom{\rule{0.2em}{0ex}}⇌\phantom{\rule{0.2em}{0ex}}{\text{H}}_{3}{\text{O}}^{+}\left(aq\right)+{\text{OH}}^{\text{−}}\left(aq\right)$

The ion product of water, K w is the equilibrium constant for the autoionization reaction:

${K}_{\text{w}}=\left[{\text{H}}_{3}{\text{O}}^{\text{+}}\right]\left[{\text{OH}}^{\text{−}}\right]=1.0\phantom{\rule{0.2em}{0ex}}×\phantom{\rule{0.2em}{0ex}}1{0}^{-14}\phantom{\rule{0.2em}{0ex}}\text{at}\phantom{\rule{0.2em}{0ex}}25\phantom{\rule{0.2em}{0ex}}\text{°C}$

## Key equations

• K w = [H 3 O + ][OH ] = 1.0 $×$ 10 −14 (at 25 °C)

## Chemistry end of chapter exercises

Write equations that show NH 3 as both a conjugate acid and a conjugate base.

One example for NH 3 as a conjugate acid: ${\text{NH}}_{2}{}^{\text{−}}+{\text{H}}^{\text{+}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{NH}}_{3};$ as a conjugate base: ${\text{NH}}_{4}{}^{\text{+}}\left(aq\right)+{\text{OH}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{NH}}_{3}\left(aq\right)+{\text{H}}_{2}\text{O}\left(l\right)$

Write equations that show ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}$ acting both as an acid and as a base.

Show by suitable net ionic equations that each of the following species can act as a Brønsted-Lowry acid:

(a) ${\text{H}}_{3}{\text{O}}^{\text{+}}$

(b) HCl

(c) NH 3

(d) CH 3 CO 2 H

(e) ${\text{NH}}_{4}{}^{\text{+}}$

(f) ${\text{HSO}}_{4}{}^{\text{−}}$

(a) ${\text{H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}^{\text{+}}\left(aq\right)+{\text{H}}_{2}\text{O}\left(l\right);$ (b) $\text{HCl}\left(l\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}^{\text{+}}\left(aq\right)+{\text{Cl}}^{\text{−}}\left(aq\right);$ (c) ${\text{NH}}_{3}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}^{\text{+}}\left(aq\right)+{\text{NH}}_{2}{}^{\text{−}}\left(aq\right);$ (d) ${\text{CH}}_{3}{\text{CO}}_{2}\text{H}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}^{\text{+}}\left(aq\right)+{\text{CH}}_{3}{\text{CO}}_{2}{}^{\text{−}}\left(aq\right);$ (e) ${\text{NH}}_{4}{}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}^{\text{+}}\left(aq\right)+{\text{NH}}_{3}\left(aq\right);$ (f) ${\text{HSO}}_{4}{}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}^{+}\left(aq\right)+{\text{SO}}_{4}{}^{\text{2−}}\left(aq\right)$

Show by suitable net ionic equations that each of the following species can act as a Brønsted-Lowry acid:

(a) HNO 3

(b) ${\text{PH}}_{4}{}^{\text{+}}$

(c) H 2 S

(d) CH 3 CH 2 COOH

(e) ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}$

(f) HS

Show by suitable net ionic equations that each of the following species can act as a Brønsted-Lowry base:

(a) H 2 O

(b) OH

(c) NH 3

(d) CN

(e) S 2−

(f) ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}$

(a) ${\text{H}}_{2}\text{O}\left(l\right)+{\text{H}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}_{3}{\text{O}}^{\text{+}}\left(aq\right);$ (b) ${\text{OH}}^{\text{−}}\left(aq\right)+{\text{H}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}_{2}\text{O}\left(l\right);$ (c) ${\text{NH}}_{3}\left(aq\right)+{\text{H}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{NH}}_{4}{}^{\text{+}}\left(aq\right);$ (d) ${\text{CN}}^{\text{−}}\left(aq\right)+{\text{H}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{HCN}\left(aq\right);$ (e) ${\text{S}}^{2-}\left(aq\right)+{\text{H}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{HS}}^{\text{−}}\left(aq\right);$ (f) ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}\left(aq\right)+{\text{H}}^{\text{+}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}_{3}{\text{PO}}_{4}\left(aq\right)$

Show by suitable net ionic equations that each of the following species can act as a Brønsted-Lowry base:

(a) HS

(b) ${\text{PO}}_{4}{}^{\text{3−}}$

(c) ${\text{NH}}_{2}{}^{\text{−}}$

(d) C 2 H 5 OH

(e) O 2−

(f) ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}$

What is the conjugate acid of each of the following? What is the conjugate base of each?

(a) OH

(b) H 2 O

(c) ${\text{HCO}}_{3}{}^{\text{−}}$

(d) NH 3

(e) ${\text{HSO}}_{4}{}^{\text{−}}$

(f) H 2 O 2

(g) HS

(h) ${\text{H}}_{5}{\text{N}}_{2}{}^{\text{+}}$

(a) H 2 O, O 2− ; (b) H 3 O + , OH ; (c) H 2 CO 3 , ${\text{CO}}_{3}{}^{\text{2−}};$ (d) ${\text{NH}}_{4}{}^{\text{+}},$ ${\text{NH}}_{2}{}^{\text{−}};$ (e) H 2 SO 4 , ${\text{SO}}_{4}{}^{\text{2−}};$ (f) ${\text{H}}_{3}{\text{O}}_{2}{}^{\text{+}},$ ${\text{HO}}_{2}{}^{\text{−}};$ (g) H 2 S; S 2− ; (h) ${\text{H}}_{6}{\text{N}}_{2}{}^{2+},$ H 4 N 2

What is the conjugate acid of each of the following? What is the conjugate base of each?

(a) H 2 S

(b) ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}$

(c) PH 3

(d) HS

(e) ${\text{HSO}}_{3}{}^{\text{−}}$

(f) ${\text{H}}_{3}{\text{O}}_{2}{}^{\text{+}}$

(g) H 4 N 2

(h) CH 3 OH

Identify and label the Brønsted-Lowry acid, its conjugate base, the Brønsted-Lowry base, and its conjugate acid in each of the following equations:

(a) ${\text{HNO}}_{3}+{\text{H}}_{2}\text{O}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}_{3}{\text{O}}^{\text{+}}+{\text{NO}}_{3}{}^{\text{−}}$

(b) ${\text{CN}}^{\text{−}}+{\text{H}}_{2}\text{O}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{HCN}+{\text{OH}}^{\text{−}}$

(c) ${\text{H}}_{2}{\text{SO}}_{4}+{\text{Cl}}^{\text{−}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{HCl}+{\text{HSO}}_{4}{}^{\text{−}}$

(d) ${\text{HSO}}_{4}{}^{\text{−}}+{\text{OH}}^{\text{−}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{SO}}_{4}{}^{\text{2−}}+{\text{H}}_{2}\text{O}$

(e) ${\text{O}}^{2-}+{\text{H}}_{2}\text{O}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}2{\mathrm{OH}}^{\text{−}}$

(f) ${\left[\text{Cu}{\left({\text{H}}_{2}\text{O}\right)}_{3}\left(\text{OH}\right)\right]}^{\text{+}}+{\left[\text{Al}{\left({\text{H}}_{2}\text{O}\right)}_{6}\right]}^{3+}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\left[\text{Cu}{\left({\text{H}}_{2}\text{O}\right)}_{4}\right]}^{2+}+{\left[\text{Al}{\left({\text{H}}_{2}\text{O}\right)}_{5}\left(\text{OH}\right)\right]}^{2+}$

(g) ${\text{H}}_{2}\text{S}+{\text{NH}}_{2}{}^{\text{−}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{HS}}^{\text{−}}+{\text{NH}}_{3}$

The labels are Brønsted-Lowry acid = BA; its conjugate base = CB; Brønsted-Lowry base = BB; its conjugate acid = CA. (a) HNO 3 (BA), H 2 O(BB), H 3 O + (CA), ${\text{NO}}_{3}{}^{\text{−}}\left(\text{CB}\right);$ (b) CN (BB), H 2 O(BA), HCN(CA), OH (CB); (c) H 2 SO 4 (BA), Cl (BB), HCl(CA), ${\text{HSO}}_{4}{}^{\text{−}}\left(\text{CB}\right);$ (d) ${\text{HSO}}_{4}{}^{\text{−}}\left(\text{BA}\right),$ OH (BB), ${\text{SO}}_{4}{}^{\text{2−}}$ (CB), H 2 O(CA); (e) O 2− (BB), H 2 O(BA) OH (CB and CA); (f) [Cu(H 2 O) 3 (OH)] + (BB), [Al(H 2 O) 6 ] 3+ (BA), [Cu(H 2 O) 4 ] 2+ (CA), [Al(H 2 O) 5 (OH)] 2+ (CB); (g) H 2 S(BA), ${\text{NH}}_{2}{}^{\text{−}}\left(\text{BB}\right),$ HS (CB), NH 3 (CA)

Identify and label the Brønsted-Lowry acid, its conjugate base, the Brønsted-Lowry base, and its conjugate acid in each of the following equations:

(a) ${\text{NO}}_{2}{}^{\text{−}}+{\text{H}}_{2}\text{O}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{HNO}}_{2}+{\text{OH}}^{\text{−}}$

(b) $\text{HBr}+{\text{H}}_{2}\text{O}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}_{3}{\text{O}}^{\text{+}}+{\text{Br}}^{\text{−}}$

(c) ${\text{HS}}^{\text{−}}+{\text{H}}_{2}\text{O}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}_{2}\text{S}+{\text{OH}}^{\text{−}}$

(d) ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}+{\text{OH}}^{\text{−}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{HPO}}_{4}{}^{\text{2−}}+{\text{H}}_{2}\text{O}$

(e) ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}+\text{HCl}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}_{3}{\text{PO}}_{4}+{\text{Cl}}^{\text{−}}$

(f) ${\left[\text{Fe}{\left({\text{H}}_{2}\text{O}\right)}_{5}\left(\text{OH}\right)\right]}^{2+}+{\left[\text{Al}{\left({\text{H}}_{2}\text{O}\right)}_{6}\right]}^{3+}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{[Fe}{\left({\text{H}}_{2}\text{O}\right)}_{6}\right]}^{3+}+{\left[\text{Al}{\left({\text{H}}_{2}\text{O}\right)}_{5}\left(\text{OH}\right)\right]}^{2+}$

(g) ${\text{CH}}_{3}\text{OH}+{\text{H}}^{\text{−}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{CH}}_{3}{\text{O}}^{\text{−}}+{\text{H}}_{2}$

What are amphiprotic species? Illustrate with suitable equations.

Amphiprotic species may either gain or lose a proton in a chemical reaction, thus acting as a base or an acid. An example is H 2 O. As an acid:
${\text{H}}_{2}\text{O}\left(aq\right)+{\text{NH}}_{3}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⇌\phantom{\rule{0.2em}{0ex}}{\text{NH}}_{4}{}^{\text{+}}\left(aq\right)+{\text{OH}}^{\text{−}}\left(aq\right).$ As a base: ${\text{H}}_{2}\text{O}\left(aq\right)+\text{HCl}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⇌\phantom{\rule{0.2em}{0ex}}{\text{H}}_{3}{\text{O}}^{\text{+}}\left(aq\right)+{\text{Cl}}^{\text{−}}\left(aq\right)$

State which of the following species are amphiprotic and write chemical equations illustrating the amphiprotic character of these species:

(a) H 2 O

(b) ${\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}$

(c) S 2−

(d) ${\text{CO}}_{3}{}^{\text{2−}}$

(e) ${\text{HSO}}_{4}{}^{\text{−}}$

State which of the following species are amphiprotic and write chemical equations illustrating the amphiprotic character of these species.

(a) NH 3

(b) ${\text{HPO}}_{4}{}^{\text{−}}$

(c) Br

(d) ${\text{NH}}_{4}{}^{\text{+}}$

(e) ${\text{ASO}}_{4}{}^{\text{3−}}$

amphiprotic: (a) ${\text{NH}}_{3}+{\text{H}}_{3}{\text{O}}^{\text{+}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{NH}}_{4}\text{OH}+{\text{H}}_{2}\text{O},$ ${\text{NH}}_{3}+{\text{OCH}}_{3}{}^{\text{−}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{NH}}_{2}{}^{\text{−}}+{\text{CH}}_{3}\text{OH};$ (b) ${\text{HPO}}_{4}{}^{\text{2−}}+{\text{OH}}^{\text{−}}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{PO}}_{4}{}^{\text{3−}}+{\text{H}}_{2}\text{O},$ ${\text{HPO}}_{4}{}^{\text{2−}}+{\text{HClO}}_{4}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{H}}_{2}{\text{PO}}_{4}{}^{\text{−}}+{\text{ClO}}_{4}{}^{\text{−}};$ not amphiprotic: (c) Br ; (d) ${\text{NH}}_{4}{}^{\text{+}};$ (e) ${\text{AsO}}_{4}{}^{\text{3−}}$

Is the self ionization of water endothermic or exothermic? The ionization constant for water ( K w ) is 2.9 $×$ 10 −14 at 40 °C and 9.3 $×$ 10 −14 at 60 °C.

give two properties of liquid
what is measurement
is the comparison of an unknown quantity with a fixed quantity of the same kind
How does an element differ from a compound? How are they similar?
an element is an indivisible particles that can take part in a reaction and consist of smaller or tiny particles i.e proton, neutrons and electron while a compound is when two or more element chemically combine together. They are similar when they are homogeneous compound. they take the same rxn.
Yusuf
an element is s chemically pure substance containing a particular type of atoms.. A COMPOUND is a substance containing atoms from different elements..
Inemesit
How to get the Lewis formula of SeCl+3
hi,I'm new here can I join the conversation
EZEA
what is the structural formula for starch
Starch is a mixture (of chemicals) of amylose and amylopectin. Both are macromolecules and polymers. You can search on wikipedia.
Abdelkarim
what is the roles of filter bed
Fathmat
what is the roles of Alu m
Fathmat
what is the roles of chlorine
Fathmat
Roles can be classified or correlate it to different areas: For example: Chlorine can be used in reactions (in industry) to manufacture HCl, which then can be used for other things. Or in swimming pools to kill bacteria. Or as a component in compounds with pharmaceutical roles (drugs). For Al:
Abdelkarim
Its dentisty value is suitable to be used in alloys (mixture of metals) in aircraft bodies. Also, Aluminium foils, Tin cans,.. Some of them are also in Al overhead cables in streets and long roads.
Abdelkarim
what is chemistry
Maxamed
what is the meaning of exceedingly
it is an adverb which means extremely
Rohini
what is atomic chemistry?
Lewis structure for no3
Lewis structure for no3
what is weak acid
It is an acid which partially ionises in water.
Abdelkarim
what is incandescence
Clifton
what makes it glow
Clifton
why is it red, irange and yellow in color
Clifton
hello am new here and I want to join you
Aliyu
hello
Clifton
hi
Aliyu
too
Gillian
hello i am new here please i want to join this group
Paul
Hi, I'm also new here
Salaudeen
Hi
Keeya
hello guys !!
Sourav
what is pressure?
The force applied to suction Area of the body
Ahmed
Matter composed of exceedingly small paticle called atom.
Yushao
questions related to metals
occurrence and preparation of the representatives metals
Regina
list the 20, periodic table and their symbols
hydrogen:h helium;he lithium:l beryllium:be Boron:b Carbon;C Nitrogen:n Oxygen:O FLUORINE:f Neon:n Sodium:s Magnesium:mg Aluminum:a Silicon:s Phosphorus:p Sulphur:s Chlorine:c Argon;a Potassium:p Calcium:c
Benita
Hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, magnesium, aluminium, silicon, phosphorus, sulphur, chlorine, argon, potassium, calcium
Cudjoe
what is a solute
Any substance that is disolved in a liqid solvent to create a solution
Fifa
sorry liquid
Fifa
it's a liquid substance
Fathmat
hello group
Ayomide
is the substance that dissolves in the solvent
Amos
so is HCl ionic compound
No, covalent compound ➡️ molecule. As both H and Cl are non-metals and and form covalent bind by sharing valence e-. But can fully ionice in water forming H+ (a proton, a reason for acidity) and Cl- (anion =Chloride) Hydrogen Chloride is a gas at room; Hydrochloric acid = HCl (aq), dissolved in w
Abdelkarim
Form covalenr bond*
Abdelkarim
The question marks are an emoji in the first sentence is an unread emoji. HCl Covalent compund -> molecule
Abdelkarim
Hi.
Queen
Hi
Calvin
Yh
Cudjoe
yes
Amos
what is chemistry
is the study of composition of substances and the way they behave under different conditions
Amos
how do calculate n1 though n6 any help on understanding the concept
Clifton
is the study of properties of matter and it's component
Grace
where can I get the test bank or mcqs ? any idea ? By By By Madison Christian By Anh Dao By OpenStax By Szilárd Jankó By Anh Dao By Dewey Compton By Yasser Ibrahim By David Corey By John Gabrieli By Nick Swain