Oxidation State
MCQs for CSIR NET & GATE
Coordination Compounds
Topic wise Assignment 1
Q1. The complex formed in the brown ring test for nitrates is
(b) [Fe(H2O)5NO]2+
(c) [Fe(H2O)4(NO)2]2+
(d) [Fe(H2O)4(NO)2]3+
Q2. The structures of the complexes [Cu(NH3)4](ClO4)2 and [Cu(NH3)4](ClO4) in solution respectively are
(b) Octahedral and square pyramidal
(c) Octahedral and trigonal bipyramidal
(d) Tetrahedral and square planer
Q3. The oxidation number of Fe in Na2[Fe(CN)5NO] is
(a) +1
(b) +2
(c) +3
(d) +4
Q4. The molecular formula for tetraamminenickel(II)hexacyanoferrate(III) is?
(a) [Ni(NH3)4] [Fe(CN)6]
(b) [Ni(NH3)4]3 [Fe(CN)6]4
(c) [Ni(NH3)4] [Fe(CN)6]2
(d) [Ni(NH3)4]3 [Fe(CN)6]2
Q5. Which of the following can't act as a chelating agent?
(b) CH3NHCH2CH3
(c) N(CH2CH2NH2)3
(d) H2NCH2CH2CH2NH2
Q6. For Co in oxidation state= +2; what will be the overall charges on following complexes
(a) z = +2 ; x = -2 ; y = +2
(b) z = 0 ; x = +2 ; y = -2
(c) z = 0 ; x = +2 ; y = +2
(d) z = -2 ; x = +2 ; y = -2
Q7. The three dimensional structure of compound [Co(Co(NH3)4(OH)2)3]Br6 has
(b) Ten Co-O and Ten Co-N bonds
(c) Fourteen Co-O and Ten Co-N bonds
(d) Twelve Co-O and Ten Co-N bonds
Q8. Among the following, species expected to show fluxional behavior are
(B) IF7 , Pentagonal Bipyramidal
(C) [CoF6]3- , Octahedral
(D) Fe(CO)5 , Trigonal Bipyramidal
(a) B and C
(b) B and D
(c) C and D
(d) A and D
Q9. In the following hexa-coordinated complexes
(I) CoCl3(NH3)6
(II) CoCl3(NH3)5
(III) CoCl3(NH3)4
If the number coordinated NH3 molecules in (I), (II) and (III) respectively are 6, 5 and 4 then the oxidation states of Cobalt in (I), (II) and (III) will respectively be
(a) +6, +5, +4
(b) +3, +2, +1
(c) 0, +1, +2
(d) +3, +3, +3
Q10. A complex is composed of one chromium ion, three bromides and six water molecules. Upon addition of excess AgNO3, 1.0 gram aqueous solution of the complex gave 0.94g of AgBr. The molecular formula of the complex is
(b) [Cr(H2O)5Br]Br2.H2O
(c) [Cr(H2O)4Br2]Br.2H2O
(d) [Cr(H2O)3Br3].3H2O
Answer Key
Q1.b Q2.a Q3.b Q4.d Q5.b Q6.b Q7.a Q8.b Q9.d Q10.b