If ${\mathrm{pK}}_{\mathrm{b}}$ for fluoride ion at $25°\mathrm{C}$ is 10.83, the ionization constant of hydrofluoric acid at this temperature is

1. $1.74\times {10}^{-5}$

2. $3.52\times {10}^{-3}$

3. $6.75\times {10}^{-4}$

4. $5.38\times {10}^{-2}$

The pK_a of HCN is 9.30. The pH of a solution prepared by mixing 2.5 moles of KCN and 2.5 moles of HCN in water and making up the total volume to 500 ml will be:

What is the decreasing order of strength of the bases?

${\mathrm{OH}}^{-}, {\mathrm{NH}}_2^{-}, \mathrm{H}-\mathrm{C}\equiv {\mathrm{C}}^{-} \mathrm{and} {\mathrm{CH}}_3-{\mathrm{CH}}_2^{-}?$

1. ${\mathrm{CH}}_3-{\mathrm{CH}}_2^{-}>{\mathrm{NH}}_2^{-}>\mathrm{H}-\mathrm{C}\equiv {\mathrm{C}}^{-}>{\mathrm{OH}}^{-}$

2. $\mathrm{H}-\mathrm{C}\equiv {\mathrm{C}}^{-}>{\mathrm{CH}}_3-{\mathrm{CH}}_2^{-}>{\mathrm{NH}}_2^{-}>{\mathrm{OH}}^{-}$

3. ${\mathrm{OH}}^{-}>{\mathrm{NH}}_2^{-}>\mathrm{H}-\mathrm{C}\equiv {\mathrm{C}}^{-}>{\mathrm{CH}}_3-{\mathrm{CH}}_2^{-}$

4. ${\mathrm{NH}}_2^{-}>\mathrm{H}-\mathrm{C}\equiv {\mathrm{C}}^{-}>{\mathrm{OH}}^{-}>{\mathrm{CH}}_3-{\mathrm{CH}}_2^{-}$

The following equilibrium is established when hydrogen chloride is dissolved in acetic acid:

$$\(\small {\mathrm{HCl}+\mathrm{CH}_3 \mathrm{COOH} \rightleftharpoons \mathrm{Cl}^{-}+\mathrm{CH}_3 \mathrm{COOH}_2^{+}}\)

The set that characterizes the conjugate acid-base pair is:

Which of the following is an example of a reversible reaction?

A certain weak acid has a dissociation constant of $1.0\times {10}^{-4}.$ The equilibrium constant for its reaction with a strong base is

1. $1.0\times {10}^{10}$

2. $1.0\times {10}^{14}$

3. $1.0\times {10}^{-10}$

4. $1.0\times {10}^{-4}$

The precipitate of CaF₂ $({\mathrm{K}}_{\mathrm{sp}}=1.7\times {10}^{-10})$ is obtained when equal volumes of the following are mixed

1. ${10}^{-2} \mathrm{M} {\mathrm{Ca}}^{2+}+{10}^{-3} {\mathrm{MF}}^{-}$

2. ${10}^{-3} \mathrm{M} {\mathrm{Ca}}^{2+}+{10}^{-5} {\mathrm{MF}}^{-}$

3. ${10}^{-4} \mathrm{M} {\mathrm{Ca}}^{2+}+{10}^{-4} {\mathrm{MF}}^{-}$

4. ${10}^{-5} \mathrm{M} {\mathrm{Ca}}^{2+}+{10}^{-3} {\mathrm{MF}}^{-}$

In the exothermic reaction of oxidizing SO₂ by O₂ to SO₃, what factors determine the maximum yield of SO₃?

If a solution of 0.1 M NH₄OH and 0.1 M NH₄Cl has pH 9.25, then the pK_b of NH₄OH will be:

Among the following , the compound with highest pH is : 

1. CH₃COOK

2. Na₂CO₃ 

3. NH₄Cl

4. NaNO₃