Transition metals and their many compounds act as good catalysts due to :
1. | Variable oxidation states | 2. | Unstable intermediate |
3. | Provide a suitable surface | 4. | All of the above |
Match the List I with List II:
List I (Metal ion ) |
List II (Number of unpaired electrons) |
i. Mn3+ | a. 2 |
ii. Cr3+ | b. 4 |
iii. V3+ | c. 1 |
iv. Ti3+ | d. 3 |
i | ii | iii | iv | |
1. | c | d | b | a |
2. | b | d | a | c |
3. | d | b | a | c |
4. | b | d | c | a |
The correct statement(s) about transition elements are:
1. | +2, and +3 oxidation states are more common for elements in the first transition series, while higher oxidation states are more common for the heavier elements. |
2. | The heavier transition elements form low-spin complexes only. |
3. | The atomic sizes of the elements of the first transition series are smaller than those of the heavier elements (elements of 2nd and 3r transition series). |
4. | All of the above. |
The reaction(s) involved in the preparation of potassium dichromate from iron chromite ore is/are:
1. | FeCr2O4 + NaOH + O2 → Na2CrO4 + Fe2O3 + H2O |
2. | Na2CrO4 + H2SO4 (conc.) → Na2Cr2O7 + Na2SO4 + H2O |
3. | Na2Cr2O7 + KCl→ K2Cr2O7 + NaCl |
4. | All of the above. |
For M2+/M, and M3+/M2+, the values of some metals are given in the table below:
Cr+2/Cr = -0.9 V | Cr+3/Cr+2 = -0.4V |
Mn+2/Mn = -1.2V | Mn+3/Mn+2 = +1.5 V |
Fe+2/Fe = -0.4V | Fe+3/Fe+2 = +0.8 V |
The correct inference(s) from the above data is/are:
1. | The increasing order of their stability is Mn3+< Fe3+< Cr3+ |
2. | The increasing order of the above-mentioned metals ability to get oxidized is: Fe < Cr < Mn |
3. | The increasing order of the above-mentioned metals ability to get oxidized is: Fe > Cr > Mn |
4. | Both 1 and 2 |
Consider the following graph.
Based on the graph above, it can be concluded that the element with a melting point higher than 3000 K will be:
1. | Y | 2. | X |
3. | Z | 4. | None of the above |
Zr (Z = 40) and Hf (Z = 72) have similar atomic and ionic radii because of:
1. | Lanthanoid contraction |
2. | Having similar chemical properties |
3. | Belonging to the same group |
4. | Diagonal relationship |
The transition metals generally form coloured compounds due to :
1. | Absorption of radiation to promote an electron . |
2. | Presence of ligands, the d-orbitals split up into two sets of orbitals. |
3. | Energy required to promote an electron in d subshell is low. |
4. | All of the above. |
The enthalpy of atomization of transition metals is high due to :
1. High effective nuclear charge
2. A large number of valence electrons
3. Very strong metallic bonds
4. All of the above
The correct statement regarding the element silver(Ag) is:
1. | It is a hard metal. |
2. | It is not a transition element. |
3. | It has a partially filled d orbital in a +2 oxidation state. Thus, it is a transition element. |
4. | None of the above |