Q. No.\(\mathrm{MnO}_4^{2-}\) in acidic medium, disproportionates to :
1. \(Mn_2O_7\) and MnO
2. \(MnO^-_4\) and MnO
3. \(MnO^-_4\) and \(MnO_4\)
4. \(MnO^-_4\) and \(MnO_2\)
Subtopic: Chemistry of Mn and Cr Compounds |
75%
Level 2: 60%+
Please attempt this question first.
Hints
Element 'X' is the lightest element of group 7 of periodic table which forms oxo-anion in +6 oxidation state. The colour of potassium salt of the oxo-anion is:
1. Green
2. Orange
3. Yellow
4. Brown
1. Green
2. Orange
3. Yellow
4. Brown
Subtopic: Chemistry of Mn and Cr Compounds |
69%
Level 2: 60%+
Please attempt this question first.
Hints
Consider the given reaction scheme, and read the following statements:
\(\begin{aligned} & \mathrm{NaCl}(\mathrm{~s})+\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7(\mathrm{~s}) \xrightarrow[\mathrm{H}_2 \mathrm{SO}_4]{\text { Conc }} \mathrm{A} \\ & \mathrm{~A} \xrightarrow{\mathrm{NaOH}} \mathrm{~B} \\ & \mathrm{~B} \xrightarrow{\mathrm{H}_2 \mathrm{O}_2 / \mathrm{H}_2 \mathrm{SO}_4} \mathrm{C} \end{aligned}\)
If number of \(O^{2-}_2\) ion in C= x
If number of O atom in C=y
If oxidation state of Cr in C = z
Find the value of (x+y+z) :
1. 12
2. 13
3. 16
4. 17
\(\begin{aligned} & \mathrm{NaCl}(\mathrm{~s})+\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7(\mathrm{~s}) \xrightarrow[\mathrm{H}_2 \mathrm{SO}_4]{\text { Conc }} \mathrm{A} \\ & \mathrm{~A} \xrightarrow{\mathrm{NaOH}} \mathrm{~B} \\ & \mathrm{~B} \xrightarrow{\mathrm{H}_2 \mathrm{O}_2 / \mathrm{H}_2 \mathrm{SO}_4} \mathrm{C} \end{aligned}\)
If number of \(O^{2-}_2\) ion in C= x
If number of O atom in C=y
If oxidation state of Cr in C = z
Find the value of (x+y+z) :
1. 12
2. 13
3. 16
4. 17
Subtopic: Chemistry of Mn and Cr Compounds |
Please attempt this question first.
Hints
Please attempt this question first.
Which of the following oxidation reactions are carried out by both \(\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7\) and \(\mathrm{KMnO}_4\) in acidic medium?
A. \(\mathrm{I}^{-} \rightarrow \mathrm{I}_2\)
B. \(\mathrm{S}^{2-} \rightarrow \mathrm{S}\)
C. \(\mathrm{Fe}^{2+} \rightarrow \mathrm{Fe}^{3+}\)
D. \(\mathrm{I}^{-} \rightarrow \mathrm{IO}_3^{-}\)
E. \(\mathrm{S}_2 \mathrm{O}_3^{2-} \rightarrow \mathrm{SO}_4^{2-}\)
Choose the correct answer from the options given below:
1. B, C and D only
2. A, D and E only
3. A, B and C only
4. C, D and E only
A. \(\mathrm{I}^{-} \rightarrow \mathrm{I}_2\)
B. \(\mathrm{S}^{2-} \rightarrow \mathrm{S}\)
C. \(\mathrm{Fe}^{2+} \rightarrow \mathrm{Fe}^{3+}\)
D. \(\mathrm{I}^{-} \rightarrow \mathrm{IO}_3^{-}\)
E. \(\mathrm{S}_2 \mathrm{O}_3^{2-} \rightarrow \mathrm{SO}_4^{2-}\)
Choose the correct answer from the options given below:
1. B, C and D only
2. A, D and E only
3. A, B and C only
4. C, D and E only
Subtopic: Chemistry of Mn and Cr Compounds |
72%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
\(\mathrm{KMnO}_4\) oxidises others in an acidic medium, the difference between the two oxidation states of \(\mathrm{Mn}\) is \(\mathrm{x.}\) Neutral \(\mathrm{FeCl}_3\) reacts with oxalate to form a complex compound having y d-electrons. Find \(\mathrm{x+y.}\)
| 1. | \(5\) | 2. | \(10\) |
| 3. | \(6\) | 4. | \(8\) |
Subtopic: Chemistry of Mn and Cr Compounds |
63%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
Which of the following statements are true?
1. (i) and (ii)
2. (iii) and (iv)
3. (i) and (iv)
4. (iii) and (v)
| (i) | The chromate ion is square planar. |
| (ii) | The green manganate ion is diamagnetic. |
| (iii) | Dichromate can be prepared using chromate. |
| (iv) | Dark green \(\text{KMnO}_4\) disproportionates in acidic and neutral mediums. |
| (v) | For d-block elements, ionic character decreases for increasing oxidation numbers of the metal in oxides. |
1. (i) and (ii)
2. (iii) and (iv)
3. (i) and (iv)
4. (iii) and (v)
Subtopic: Chemistry of Mn and Cr Compounds |
58%
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.
Consider the given reaction:
\(\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7+\mathrm{H}_2 \mathrm{O}_2+\mathrm{H}_2 \mathrm{SO}_4 \xrightarrow[\text { conditions }]{\text { ether cold }} \text { compound ' } \mathrm{X} \text { ' }\)
\(\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7+\mathrm{H}_2 \mathrm{O}_2+\mathrm{H}_2 \mathrm{SO}_4 \xrightarrow[\text { conditions }]{\text { ether cold }} \text { compound ' } \mathrm{X} \text { ' }\)
X is a chromium compound. Determine the oxidation state of chromium in compound 'X'.
| 1. | \(+6\) | 2. | \(+3\) |
| 3. | \(+5\) | 4. | \(+10\) |
Subtopic: Chemistry of Mn and Cr Compounds |
57%
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.
During the qualitative analysis of SO₃²⁻ using acidified H₂SO₄, SO₂ gas is evolved. This gas turns K₂Cr₂O₇ solution:
1. Green
2. Black
3. Blue
4. Red
1. Green
2. Black
3. Blue
4. Red
Subtopic: Chemistry of Mn and Cr Compounds |
81%
Level 1: 80%+
Please attempt this question first.
Hints
Please attempt this question first.
When K2Cr2O7 is used in an acidic medium during titration, the oxidation number of Cr in the product side is-
1. +6
2. +2
3. +3
4. +4
1. +6
2. +2
3. +3
4. +4
Subtopic: Chemistry of Mn and Cr Compounds |
62%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
When acidified \(KMnO_4 \) reacts with oxalic acid gives a manganese product. Find the magnetic moment (spin only) of \(Mn\) in this product:
1. 2
2. 6
3. 0
4. 4
1. 2
2. 6
3. 0
4. 4
Subtopic: Chemistry of Mn and Cr Compounds |
70%
Level 2: 60%+
Please attempt this question first.
Hints
Please attempt this question first.
© 2026 GoodEd Technologies Pvt. Ltd.