Conjugate Acids and Bases

Q.

Is ${\mathrm{NH}}_4\mathrm{Br}$ an acid or base?

Q. The $p{K}_b$ for fluoride ion at ${25}^{\circ }C$ is $10.83$. The ionisation constant of hydrofluoric acid at this temperature is:
$antilog\overline{4}.83=6.76\times {10}^{-4}$

1. $6.76\times {10}^{-4}$
2. $1.74\times {10}^{-5}$
3. $5.38\times {10}^{-2}$
4. $3.52\times {10}^{-3}$

Q. According to Bronsted - Lowry's Acids and Bases concept, select the species which can act as an acid as well as a base ?

1. $C{l}^{-}$
2. $HS{O}_4^{-}$
3. $S{O}_4^{2-}$
4. $S^{2-}$

Q. According to Bronsted-Lowry concept, the correct order of relative strength of bases follows the order:

1. $C{H}_{3}CO{O}^{-}>C{l}^{-}>O{H}^{-}$
2. $C{H}_{3}CO{O}^{-}>O{H}^{-}>C{l}^{-}$
3. $O{H}^{-}>C{H}_{3}CO{O}^{-}>C{l}^{-}$
4. $O{H}^{-}>C{l}^{-}>C{H}_{3}CO{O}^{-}$

Q. Assuming complete ionization, the pH of $0.1MHCl$ is 1. The molarity of $H_{2}S{O}_4$ with the same pH is :

1. 0.1
2. 2
3. 0.2
4. 0.05

Q. In a reaction :$HC{O}_3^{-}+H_{2}O\to C{O}_3^{2-}+H_3{O}^{+}$
$HC{O}_3^{-}$ is the conjugate acid of which Bronsted base ?

1. $H_3{O}^{+}$
2. $H_{2}C{O}_3$
3. $C{O}_3^{2-}$
4. None of the above

Q. Which of the following can be called as a conjugate acid - base pair?

1. $HCl,NaOH$
2. $H_3{O}^{+}/O{H}^{-}$
3. $H_{2}S{O}_4,HS{O}_4^{-}$
4. $H_{2}S/S^{2-}$

Q. $0.01M$ Solution of $H_{2}A$ has $pH=4$ . If $K_{a_1}$ for the acid is $4.45\times {10}^{-7}$ , the concentration of $H{A}^{-}$ ion in the solution would be :

1. $1.0\times {10}^{-2}M$
2. $4.45\times {10}^{-5}M$
3. $8.0\times {10}^{-5}M$
4. Unpredictable

Q.

What is the conjugate base of hydrazoic acid?

Q. In a reaction :$HC{O}_3^{-}+H_{2}O\to C{O}_3^{2-}+H_3{O}^{+}$
$HC{O}_3^{-}$ is the conjugate acid of which Bronsted base ?

1. $H_3{O}^{+}$
2. $H_{2}C{O}_3$
3. $C{O}_3^{2-}$
4. None of the above

Q. According to Bronsted-Lowry concept, the correct order of relative strength of bases follows the order:

1. $C{H}_{3}CO{O}^{-}>C{l}^{-}>O{H}^{-}$
2. $C{H}_{3}CO{O}^{-}>O{H}^{-}>C{l}^{-}$
3. $O{H}^{-}>C{H}_{3}CO{O}^{-}>C{l}^{-}$
4. $O{H}^{-}>C{l}^{-}>C{H}_{3}CO{O}^{-}$

Q. The conjugate acid of $N{H}_3$ is:

1. $N{H}_3$
   
2. $N{H}_4^{+}$
   
3. $N{H}_2^{-}$
4. $N{H}_{2}OH$

Q. Conjugate base of Hydrazoic acid is

1. $H{N}_3^{-}$
2. $N_2^{-}$
3. $N_3^{-}$
4. $N^{3-}$

Q. According to Bronsted - Lowry's Acids and Bases concept, select the species which can act as an acid as well as a base ?

1. $S{O}_4^{2-}$
2. $S^{2-}$
3. $HS{O}_4^{-}$
4. $C{l}^{-}$

Q.

Which of the following is the strongest conjugate base

1. $C{l}^{-}$

2. $C{H}_{3}CO{O}^{-}$

3. $S{O}_4^{2-}$

4. $N{O}_2^{-}$

Q.

Review the equilibrium and choose the correct statement

$HCl{O}_4+H_{2}O\rightleftharpoons H_3{O}^{+}+Cl{O}_4^{-}$

1. $HCl{O}_4$ is the conjugate acid of $H_{2}O$

2. $H_3{O}^{+}$ is the conjugate base of $H_{2}O$

3. $H_{2}O$ is the conjugate acid of $H_3{O}^{+}$

4. $Cl{O}_4^{-}$ is the conjugate base of $HCl{O}_4$

Q. Consider the equilibrium reaction:
$N{H}_3+H_{2}O\rightleftharpoons N{H}_4^{+}+O{H}^{-}$
Which of the following species act as a Bronsted-Lowry acid?

1. $N{H}_3$
2. $N{H}_4^{+}$
3. $H_{2}O$
4. Both (b) and (c)

Q. Choose the Lewis acids

1. $N{H}_3$
2. ${\mathrm{FeBr}}_3$
3. ${\mathrm{AlCl}}_3$
4. ${\mathrm{OH}}^{-}$
5. ${\mathrm{BF}}_3$
6. ${\mathrm{CH}}_3{\mathrm{NH}}_2$
7. ${\mathrm{CO}}_2$
8. ${\mathrm{GaCl}}_3$

Q. Consider various species generated when $H_{3}P{O}_4$ is dissolved in water. According to the Bronsted Lowry’s Concept among these, the conjugate acid of $HP{O}_4^{2-}$ is :

1. $HP{O}_4^{2-}$
2. $H_{2}P{O}_4^{-}$
3. $P{O}_4^{3-}$
4. $H_3{O}^{+}$

Q. Assuming complete ionization, the pH of $0.1MHCl$ is 1. The molarity of $H_{2}S{O}_4$ with the same pH is :

1. 0.1
2. 0.2
3. 0.05
4. 2

Q.
What is the correct order of decreasing acidic strengths?

1. $H_b>H_c>H_a$
2. $H_a>H_c>H_b$
3. $H_c>H_b>H_a$
4. $H_b>H_a>H_c$

Q. In the dissociation of $N{H}_{4}OH$, if $N{H}_{4}Cl$ is added what will be the change in $pH$ for the $N{H}_{4}OH$ solution ?

1. Decreases
2. Increases
3. No change
4. first decreases and then increases.

Q.

Write the definitions of acid and base as proposed by Arrhenius.

Q.

In which of the following reactions does $N{H}_3$ act as an acid ?

1. $N{H}_3$ + $H^{+}$ $⟶$ ${N{H}_4}^{+}$

2. $N{H}_3$ + Na $⟶$ $NaN{H}_2$ + $\frac{1}{2}$ $H_2$

3. $N{H}_3$ + HCl $⟶$ $N{H}_{4}Cl$

4. None of these

Q.

Review the equilibrium and choose the correct statement

$HCl{O}_4+H_{2}O\rightleftharpoons H_3{O}^{+}+Cl{O}_4^{-}$

1. $HCl{O}_4$ is the conjugate acid of $H_{2}O$

2. $H_3{O}^{+}$ is the conjugate base of $H_{2}O$

3. $H_{2}O$ is the conjugate acid of $H_3{O}^{+}$

4. $Cl{O}_4^{-}$ is the conjugate base of $HCl{O}_4$