Assertion: Eo for Mn3+/Mn2+ couple is more positive than for Fe3+/Fe2+.
Reason: Mn3+ has d4 configuration and Fe3+ has a d5 configuration.
Assertion: Transition metals exhibit higher enthalpies of atomization.
Reason: The atoms of transition metals are held together by strong metallic bonds.
Assertion : The transition elements form interstitial compounds.
Reason: Steel and cast iron are hard due to the formation of an interstitial compound with carbon.
Iron becomes passive by "X", it is due to the formation of "Y". X, and Y respectively are:
3. Conc. H2SO4, Fe3O4
Dil. HCl, Fe2O3
80% Conc. HNO3, Fe3O4
4. Conc. HCl, Fe3O4
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 :
Mn2+ acts as auto catalyst.
CO2 is formed.
Reaction is exothermic.
MnO4- catalyses the reaction.
The incorrect statement among the following is:
MnO2 dissolves in conc. HCl, but does not form Mn4+ ions.
MnO2 oxidizes hot concentrated H2SO4 liberating oxygen.
K2MnO4 is formed when MnO2 infused KOH is oxidized by air, KNO3, PbO2 or NaBiO3
The decomposition of acidic KMnO4 is not catalyzed by sunlight.
The addition of non-metals like B, and C to the interstitial sites of a transition metal increases-
Ductility.
Melting Point.
Shining.
Conductivity.
The metal that does not form amalgam is-
Fe
Au
Zn
Ag
The element of the first transition series having lowest oxidation potential value (M→M2++2e-) is -
Mn
Ni
Cu
The incorrect statement among the following about the chemistry of 3d and 4f series elements is -
3d elements show more oxidation states than 4f series elements.
The energy difference between 3d and 4s orbitals is very little.
Europium (ll) is more stable than Ce (ll).
The paramagnetic character in 3d series elements increases from scandium to copper.
An element among the following that have strongest metallic bond is -
Sc
V
Cr
Ionization potential values of d-block elements as compared to ionization potential value of f-block elements are :
Higher
Equal
Lower
Can't compae.
The incorrect statement among the following regarding Cerium is -
The +4 oxidation state of cerium is not known in solutions.
The +3 oxidation state of cerium is more stable than the +4 oxidation state.
The common oxidation states of cerium are +3, and +4.
Cerium (IV) acts as an oxidizing agent.
Native silver metal forms a water-soluble complex with a dilute aqueous solution of NaCN in the presence of :
Nitrogen
Oxygen
Carbon dioxide
Argon
A compound that cannot decolourise KMnO4 solution is -
CO3-2
NO2-
S-2
Cl-
Zinc can be coated on iron to produce galvanised iron but the reverse is not possible because:
Zinc is lighter than iron.
Zinc has a lower melting point than iron.
Zinc has lower negative reduction potential than iron.
Zinc has a higher negative reduction potential than iron.
The reason for greater range of oxidation states in actinoids is attributed to:
Actinoid Contraction
5f, 6d and 7s levels having comparable energies.
4f and 5d levels being close in energies.
The radioactive nature of actinoids
Match the metal ions given in Column I with the spin magnetic moments of the ions given in Column II and assign the correct code :
Column I Column II a. Co3+ i. √8 B.M.b. Cr3+ ii. √35 B.M.c. Fe3+ iii. √15 B.M. d. Ni2+ iv. √24 B.M.
a-i; b-ii; c-iii; d-iv
a-iv; b-i; c-ii; d-iii
a-iii; b-iv; c-i; d-ii
When copper is heated with conc. HNO3 it produces :
Cu(NO3) and NO
Cu(NO3)2, NO and NO2
Cu(NO3)2 and N2O
Cu(NO3)2 and NO2
Gadolinium belongs to 4f series. It’s atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?
Xe4 f8 6d2
Xe4 f9 5s1
Xe4 f7 5d16s2
Xe4 f6 5d26s2
The number of d-electrons in Fe2+ (Z = 26) is not equal to the number of :
The pair of compounds that can exist together is:
FeCl3, SnCl2
HgCl, SnCl2
FeCl2, SnCl2
FeCl3, Kl
In acidic medium, H2O2 changes Cr2O7–2 to CrO5 which has two (–O – O–) bonds Oxidation state of Cr in CrO5 is :
+5
+3
+6
-10
For the four successive transition elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order? (At. No Cr= 24, Mn= 25, Fe=26, Co= 27)
Fe>Mn>Co>Cr
Co>Mn>Fe>Cr
Cr>Mn>Co>Fe
Mn>Fe>Cr>Co
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