The approximate pH of a solution formed by mixing equal volumes of solutions of 0.1 M sodium propionate and 0.1 M propanoic acid (the dissociation constant of propanoic acid is $1.3\times {10}^{-5} \mathrm{mol} {\mathrm{dm}}^{-3}$) will be

1. 2.45

2. 4.89

3. 5.98

4. 6.89

The dissociation constant of acetic acid is \(1 . 6 \times \left(10\right)^{- 5}\). The degree of dissociation \(\left(\right. \alpha \left.\right)\) of 0.01 M acetic acid in the presence of 0.1 M HCl is equal to:
1. \(1.6 \times 10^{-3}\)
2. \(1.6 \times 10^{-1}\)
3. \(1.6 \times 10^{-6}\)
4. \(1.6 \times 10^{-4}\)

If the equilibrium constant of the reaction of weak acid HA with strong base is 10⁹, then pH of 0.1 M NaA is

1. 3

2. 9

3. 7

4. 6

If Ksp of Al(OH)₃ is $1.0\times {10}^{-15} \mathrm{M}.$ Find at what pH does $1.0\times {10}^{-3} \mathrm{M}$ Al³⁺ precipitate on the addition of buffer of NH₄Cl and NH₄OH solution.

1. 10

2. 10.5

3. 11

4. 12

The solubility of CaF₂ in water at 298 K is $1.7\times {10}^{-3}$ gm per 100 cm³. The solubility product of CaF₂ at 298 K is

1. $4.14\times {10}^{-11}$

2. $4.14\times {10}^{11}$

3. $4.14\times {10}^{-6}$

4. $4.14\times {10}^6$

A solution of monoprotic weak acid has acidity constant K_a the minimum intial concentration 'c' in terms of K_a, such that the concentration of the undissociated acid can be equated to 'c' within a 10% limit of error, would be

1. 70 K_a

2. 90 K_a

3. 50 K_a

4. 30 K_a

The solubility product of PbI₂ is $7.47\times {10}^{-9}$ at $15°\mathrm{C}$ and $1.39\times {10}^8$ at $25°\mathrm{C}$. The molar heat of solution of PbI₂ is (use log 1.86=0.2695)

1. 44.29 kJ/mol

2. 46.25 kJ/mol

3. 29.37 kJ/mol

4. 21.15 kJ/mol

Which of the following compounds is in the correct sequence in terms of relative basic strength?

1. ${\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}>\mathrm{CH}\equiv {\mathrm{C}}^{-}>{\mathrm{OH}}^{-}$

2. $\mathrm{CH}\equiv {\mathrm{C}}^{-}{>}^{-}\mathrm{OH}>{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}$

3. $\mathrm{CH}\equiv {\mathrm{C}}^{-}>{\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{OH}}^{-}$

4. ${\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}>{\mathrm{OH}}^{-}>\mathrm{CH}\equiv {\mathrm{C}}^{-}$

The concentration of CH₃COOH that will have the same [H⁺] as obtained from 10^-2 M HCOOH, is-

$\left(\mathrm{Ka}\right({\mathrm{CH}}_3\mathrm{COOH})={10}^{-5},$ $\mathrm{Ka}\left(\mathrm{HCOOH}\right)={10}^{-4})$

1. 10 M

2. 5 M

3. 10^-1 M

4. 6 M

What happens when NH₄Cl is added to an aqueous solution of NH₄OH?

1. Concentration of $\left[{\mathrm{OH}}^{-}\right]$ ions decreases.

2. Concentration of $\left[{\mathrm{OH}}^{-}\right]$ ions increases.

3. Concentration of $\left[{\mathrm{NH}}_4^{+}\right]$ ions as well as concentration $\left[{\mathrm{OH}}^{-}\right]$ ions increase.

4. Concentration of $\left[{\mathrm{NH}}_4^{+}\right]$ ions decreases.