General
✓✗In neutral or faintly alkaline medium, one mole of KMnO4 accepts
- 5 mol of electrons
- 1 mol of electrons
- 3 mol of electrons
- 2 mol of electrons
General
✓✗The electronic configuration of chromium (Z = 24) is
- [Ar]3d34s24p1
- [Ar]3d6
- [Ar]3d54s1
- [Ar]3d44s2
General
✓✗Assertion: The atomic radius of Hf is almost the same as that of Zr.
Reason: Lanthanoid contraction offsets the expected increase in size.
Reason: Lanthanoid contraction offsets the expected increase in size.
- Both Assertion and Reason are true and Reason is the correct explanation of Assertion
- Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
- Assertion is true but Reason is false
- Both Assertion and Reason are false
General
✓✗Which of the following statements is not true?
- K2Cr2O7 solution in acidic medium is orange
- Na2Cr2O7 is preferred over K2Cr2O7 in volumetric analysis
- K2Cr2O7 solution becomes yellow on increasing the pH beyond 7
- On passing H2S through acidified K2Cr2O7 solution, a milky colour is observed
General
✓✗Lanthanoids are
- 14 elements in the sixth period (atomic number 58 to 71) that are filling the 4f sublevel
- 14 elements in the seventh period (atomic number 90 to 103) that are filling the 5f sublevel
- 14 elements in the seventh period (atomic number 58 to 71) that are filling the 4f sublevel
- 14 elements in the sixth period (atomic number 90 to 103) that are filling the 4f sublevel
General
✓✗Which of the following elements is responsible for the oxidation of water to O2 in biological processes?
- Mo
- Mn
- Fe
- Cu
General
✓✗Which of the following statements about K2Cr2O7 are correct?
A. It is orange-red in colour.
B. Cr is in the +6 oxidation state.
C. In alkaline medium it changes to chromate.
D. The dichromate ion contains a Cr−Cr bond.
Choose the correct answer from the options given below.
A. It is orange-red in colour.
B. Cr is in the +6 oxidation state.
C. In alkaline medium it changes to chromate.
D. The dichromate ion contains a Cr−Cr bond.
Choose the correct answer from the options given below.
- A, B and C only
- A, B, C and D
- B and D only
- A and D only
General
✓✗The green colour formed when acidified K2Cr2O7 is reduced is due to
- Cr3+ ions
- CrO3
- CrO42− ions
- Cr2+ ions
General
✓✗Acidified KMnO4 oxidises SO32− ions to
- S
- SO2
- SO42−
- S2O32−
General
✓✗The enthalpy of atomisation in the first transition series is maximum at about
- Sc
- Cu
- Zn
- the middle of the series (V/Cr)
General
✓✗Which of the following ions has the electronic configuration [Ar]3d6? (At. nos. Mn = 25, Fe = 26, Co = 27, Ni = 28)
- Co3+
- Fe3+
- Ni3+
- Mn3+
General
✓✗An atom has the electronic configuration 1s2 2s2 2p6 3s2 3p6 3d3 4s2. It belongs to
- group 15
- group 2
- group 5
- group 3
General
✓✗The number of moles of Fe2+ oxidised by one mole of K2Cr2O7 in acidic medium is
- 5
- 6
- 2
- 3
General
✓✗On adding an alkali to an orange solution of K2Cr2O7, the solution turns
- colourless
- yellow
- green
- purple
General
✓✗Which pair of ions are both colourless?
- Ni2+ and Co2+
- Ti3+ and Cu2+
- Mn2+ and Fe3+
- Sc3+ and Zn2+