Q. No.Which of the following buffer solution will have a pH of 9.25?
(Given that \(pK_b\) of \(NH_3:4.75)\)
1. \(0.2 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.4 \ell)+0.1 ~\mathrm{M}~ \mathrm{HCl}(1 \ell) \)
2. \(0.4~ \mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(1 \ell)+0.1 ~\mathrm{M} ~\mathrm{HCl}(1 \ell) \)
3. \(0.5 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.5 \ell)+0.2 ~\mathrm{M} ~\mathrm{HCl}(0.5 \ell) \)
4. \(0.2 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.5 \ell)+0.1 ~\mathrm{M}~ \mathrm{HCl}(0.5 \ell)\)
(Given that \(pK_b\) of \(NH_3:4.75)\)
1. \(0.2 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.4 \ell)+0.1 ~\mathrm{M}~ \mathrm{HCl}(1 \ell) \)
2. \(0.4~ \mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(1 \ell)+0.1 ~\mathrm{M} ~\mathrm{HCl}(1 \ell) \)
3. \(0.5 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.5 \ell)+0.2 ~\mathrm{M} ~\mathrm{HCl}(0.5 \ell) \)
4. \(0.2 ~\mathrm{M} ~\mathrm{NH}_4 \mathrm{OH}(0.5 \ell)+0.1 ~\mathrm{M}~ \mathrm{HCl}(0.5 \ell)\)
Subtopic: pH calculation | Buffer |
Level 3: 35%-60%
Please attempt this question first.
Hints
The pH of pure water is 7.0 at 25°C. When the temperature of pure water is increased to 80°C, what happens to its pH value?
1. The pH decreases
2. The pH remains the same (still 7.0)
3. The pH first increases and then decreases
4. The pH increases
Subtopic: Introduction To Equilibrium | pH calculation |
67%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
If 1 mM solution of ethylamine produces pH = 9, then the ionization constant (Kb) of ethylamine is 10–x.
The value of x is: (nearest integer)
[Note: The degree of ionization of ethylamine can be neglected with respect to unity]
1. 5
2. 7
3. 9
4. 11
The value of x is: (nearest integer)
[Note: The degree of ionization of ethylamine can be neglected with respect to unity]
1. 5
2. 7
3. 9
4. 11
Subtopic: Ionisation Constant of Acid, Base & Salt | pH calculation |
68%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
Determine the final concentration of the weak acid \(\text {HX}\) (given \(\mathrm{K}_{\mathrm{a}}=4 \times 10^{-10}\)) after a \(0.01~ \mathrm{M}\) solution has been diluted to achieve a \(\mathrm{pH}=6\). Express this final concentration in the form \(\mathrm{x \times 10^{-4} M}\), and then state the numerical value of x:
1. 14
2. 25
3. 31
4. 12
1. 14
2. 25
3. 31
4. 12
Subtopic: pH calculation |
71%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
If the concentration of \(\text{H}^+\) ions is increased by a factor of 1000, what will happen to the pH?
1. Decreased by 3
2. Increased by 3
3. There is no change in pH
4. Decreased by 1
1. Decreased by 3
2. Increased by 3
3. There is no change in pH
4. Decreased by 1
Subtopic: pH calculation |
80%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
The pH of the solution obtained by mixing 600 mL of 0.04 M HCl and 400 mL of 0.02 M H2SO4 is:
[log 4 = 0.6]
1. 3.4
2. 5.4
3. 1.4
4. 2.4
Subtopic: pH calculation |
80%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Subtopic: pH calculation |
89%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
pH of a buffer solution of \(CH_3CH_2COOH(aq.)~\&~CH_3CH_2COONa(aq.) \) is 4.
Then, the ratio of \(\frac{[CH_3CH_2COO^-]}{[CH_3CH_2COOH]}\) is-
(Given \(K_a=10^{-5} \))
1. 0.1
2. 10
3. 0.2
4. 20
Then, the ratio of \(\frac{[CH_3CH_2COO^-]}{[CH_3CH_2COOH]}\) is-
(Given \(K_a=10^{-5} \))
1. 0.1
2. 10
3. 0.2
4. 20
Subtopic: pH calculation |
70%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
When 50 mL, 0.1 M CH3COOH (aq.) is titrated with 25 mL of 0.1 M NaOH (aq) solution. What is the value of the pH of the resulting solution?
[Given: pKa=4.76]
1. 3.76
2. 6.76
3. 4.76
4. 5.76
[Given: pKa=4.76]
1. 3.76
2. 6.76
3. 4.76
4. 5.76
Subtopic: pH calculation | Buffer |
80%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
If 200 mL of 0.01 M HCl is mixed with 400 mL of 0.01 M H2SO4, what is the pH of the resulting mixture?
(Given: log 2 = 0.30, log 3 = 0.48, log 5 = 0.70, log 7 = 0.84, log 11 = 1.04)
1. 1.14
2. 1.78
3. 2.34
4. 3.02
(Given: log 2 = 0.30, log 3 = 0.48, log 5 = 0.70, log 7 = 0.84, log 11 = 1.04)
1. 1.14
2. 1.78
3. 2.34
4. 3.02
Subtopic: pH calculation |
74%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
© 2026 GoodEd Technologies Pvt. Ltd.