Q. No.\(\text{Ka}\) values of three acids \(\text{A, B}\) and \(\text{C}\) are \(10^{-3}, 5 \times\)\(10^{-9}, 9 \times 10^{-11}\) respectively. The acidic strength order of these acids is:
1. \(\text{A}>\text{B}>\text{C}\)
2. \(\text{B}>\text{A}>\text{C}\)
3. \(\text{C}>\text{B}>\text{A}\)
4. \(\text{C}>\text{A}>\text{B}\)
Subtopic: Acids & Bases - Definitions & Classification |
90%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
Decreasing order of Lewis acid character is:
1. BF3 > BCl3 > BBr3 > BI3
2. BI3 > BBr3 > BCl3 > BF3
3. BF3 > BCl3 > BI3 > BBr3
4. BI3 > BCl3 > BF3 > BBr3
1. BF3 > BCl3 > BBr3 > BI3
2. BI3 > BBr3 > BCl3 > BF3
3. BF3 > BCl3 > BI3 > BBr3
4. BI3 > BCl3 > BF3 > BBr3
Subtopic: Acids & Bases - Definitions & Classification |
72%
Level 2: 60%+
Please attempt this question first.
Hints
Given below are two statements:
In light of the above statements choose the correct answer from the options given below:
| Statement I: | According to Lewis's concept, H2O acts as an amphoteric substance. |
| Statement II: | H2O act as an acid on reaction with NH3, while it acts as a base on reaction with H2S. |
| 1. | Both Statement I and Statement II are correct. |
| 2. | Both Statement I and Statement II are incorrect. |
| 3. | Statement I is correct and Statement II is incorrect. |
| 4. | Statement I is incorrect and Statement II is correct. |
Subtopic: Acids & Bases - Definitions & Classification |
Level 4: Below 35%
Please attempt this question first.
Hints
Please attempt this question first.
Given below are two statements:
| Assertion (A): | The amphoteric nature of water is explained by using Lewis acid/base concept. |
| Reason (R): | Water acts as an acid with \(\mathrm {NH}_3\) and as a base with \(\mathrm {H_2S}\). |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
Subtopic: Acids & Bases - Definitions & Classification |
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.
The exact volumes of \(1~ M~ NaOH\) solution required to neutralise \(50 ~mL\) of \(1 ~M~H_3PO_3\) solution and \(100 ~mL\) of \(2 ~M~ H_3PO_2\) solution, respectively, are :
1. \(100 ~mL\) and \(50~ mL\)
2. \(100 ~mL\) and \(100 ~mL\)
3. \(100 ~mL\) and \(200 ~mL\)
4. \(50~ mL\) and \(50~ mL\)
1. \(100 ~mL\) and \(50~ mL\)
2. \(100 ~mL\) and \(100 ~mL\)
3. \(100 ~mL\) and \(200 ~mL\)
4. \(50~ mL\) and \(50~ mL\)
Subtopic: Acids & Bases - Definitions & Classification | pH calculation |
82%
Level 1: 80%+
Please attempt this question first.
Hints
Which of the following compound cannot act as a Lewis base?
1. \(ClF_3\)
2. \(SF_4\)
3. \(PCl_5\)
4. \(NF_3\)
1. \(ClF_3\)
2. \(SF_4\)
3. \(PCl_5\)
4. \(NF_3\)
Subtopic: Acids & Bases - Definitions & Classification |
67%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
\(0.01\) moles of a weak acid \(HA (K_a = 2.0 × 10^{–6} )\) is dissolved in \(1.0 ~L ~\text{of}~ 0.1~ M~ HCl\) solution. If the degree of dissociation of \(HA\) is \(x × 10^{–5}\) , find the value of \(x\) (rounded off to the nearest integer):
[Note: Neglect volume change on adding \(HA.\)]
1. One (1)
2. Two (2)
3. Three (3)
4. Four (4)
[Note: Neglect volume change on adding \(HA.\)]
1. One (1)
2. Two (2)
3. Three (3)
4. Four (4)
Subtopic: Ionisation Constant of Acid, Base & Salt | Acids & Bases - Definitions & Classification |
71%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
100 mL of 0.1 M HCl is taken in a beaker and to it 100 mL of 0.1 M NaOH is added in steps of 2 mL and the pH is continuously measured. Which of the following graphs correctly depicts the change in pH?
| 1. |  |
2. |  |
| 3. |  |
4. |  |
Subtopic: Acids & Bases - Definitions & Classification |
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.
Consider the following statements
| a. | The correct order of increasing acidic strength is CH4 < NH3 < HF < H2O. |
| b. | The ionic product of water is temperature dependent. |
| c. | A monobasic acid with Ka = 10–5 has a pH = 5. The degree of dissociation of this acid is 50%. |
The correct statements are:
1. (a) and (b)
2. (a), (b) and (c)
3. (a) and (c)
4. (b) and (c)
Subtopic: Acids & Bases - Definitions & Classification |
50%
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.
The species, among the following, that act as both Brönsted acid and base is/are:
1. \(H_2PO^-_2 \)
2. \(HPO^{2-}_3\)
3. \(HPO^{2-}_4\)
4. All of the above
Subtopic: Acids & Bases - Definitions & Classification |
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.
© 2026 GoodEd Technologies Pvt. Ltd.