Q. No.When KMnO4 solution is added to hot oxalic acid solution, the decolorization is slow in the beginning but becomes instantaneous after some time. This is because :
1. acts as auto catalyst.
2. is formed.
3. Reaction is exothermic.
4. catalyses the reaction.
Find the false statement among the following regarding manganese compounds.
1. MnO₂ dissolves in concentrated HCl, but does not form Mn⁴⁺ ions.2. MnO₂ oxidises hot concentrated H₂SO₄, liberating oxygen.
3. K₂MnO₄ is formed when MnO₂ fused with KOH is oxidised by air, KNO₃, PbO₂, or NaBiO₃.
4. The decomposition of acidic KMnO₄ is not catalysed by sunlight.
The addition of non-metals like B and C to the interstitial sites of a transition metal increases
1. Ductility
2. Melting Point
3. Shining
4. Conductivity
The element of the first transition series having lowest oxidation potential value is -
1. Mn
2. Fe
3. Ni
4. Cu
The incorrect statement among the following about the chemistry of 3d and 4f series elements is
| 1. | 3d elements show more oxidation states than 4f series elements. |
| 2. | The energy difference between 3d and 4s orbitals is very little. |
| 3. | Europium (ll) is more stable than Ce (ll). |
| 4. | The paramagnetic character of the 3d series elements increases from scandium to copper. |
The ionization potential values of d-block elements as compared to the ionization potential values of f-block elements are:
| 1. | Higher | 2. | Equal |
| 3. | Lower | 4. | Can't compare. |
The incorrect statement among the following regarding Cerium is :
| 1. | The +4 oxidation state of cerium is not known in solutions. |
| 2. | The +3 oxidation state of cerium is more stable than the +4 oxidation state. |
| 3. | The common oxidation states of cerium are +3, and +4. |
| 4. | Cerium (IV) acts as an oxidizing agent. |
The native silver metal forms a water-soluble complex with a dilute aqueous solution of NaCN in the presence of :
1. Nitrogen
2. Oxygen
3. Carbon dioxide
4. Argon
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