d- and f-Block Elements PYQs Set 5 (PDF)

Set 5 of 14 · Questions 121-150 of 399

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Mere Teacher · Previous Year Questions NEET Chemistry · d- and f-Block Elements · Set 5 (Q121-150)
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121. $Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy ?$ (1) $Vanadium (Z = 23)$ (2) $Manganese (Z = 25)$ (3) $Chromium (Z = 24)$ (4) $Iron (Z = 26)$ 122. $The valence shell electronic configuration of Cr and Cu atoms, respectively, are$ (1) $3 d^{4} 4 s^{2}; 3 d^{10} 4 s^{1}$ (2) $3 d^{5} 4 s^{1}; 3 d^{10} 4 s^{1}$ (3) $3 d^{5} 4 s^{1}; 3 d^{9} 4 s^{2}$ (4) $3 d^{4} 4 s^{2}; 3 d^{9} 4 s^{2}$ 123. $The highest magnetic moment is shown by the transition metal ion with the configuration$ (1) $3 d^{2}$ (2) $3 d^{5}$ (3) $3 d^{7}$ (4) $3 d^{9}$ 124. $The number of ions from the following that have the ability to liberate hydrogen from a dilute acid is Ti^{2 +}, Cr^{2 +} and V^{2 +}$ (1) $2$ (2) $3$ (3) $1$ (4) $0$ 125. $Which of the following is not arranged in the correct sequence?$ (1) $MO, M_{2} O_{3}, M_{2}, M_{2} O_{5} (Decreasing basic nature)$ (2) $Sc, V, Cr, Mn (Increasing number of oxidation states)$ (3) $d^{5}, d^{3}, d^{1}, d^{4} (Increasing magnetic moment)$ (4) $Mn^{2 +}, Fe^{2 +}, Cr^{2 +}, Co^{2 +} (Decreasing stability)$ 126. $The electronic configuration of transition element X, is +3 , oxidation state is [Ar] 3 d^{5} . What is its atomic number?$ (1) $25$ (2) $26$ (3) $27$ (4) $24$ 127. $In which of the following pairs are both the ions coloured in aqueous solution?.(At. no. : S c = 21, T i = 22, N i = 28, C u = 29, C o = 27)$ (1) $N i^{2 +}, C u^{+}$ (2) $N i^{2 +}, T i^{3 +}$ (3) $S c^{3 +}, T i^{3 +}$ (4) $S c^{3 +}, C o^{2 +} .$ 128. $KMnO4 acts as an oxidising agent in the neutral medium and gets reduced to MnO2. The equivalent weight of KMnO4 in neutral medium will be :$ (1) $mol. wt. / 2$ (2) $mol. wt. / 3$ (3) $mol. wt. / 4$ (4) $mol. wt. / 7$ 129. $The atomic numbers of V, Cr, Mn and Fe are respectively 23, 24, 25 and 26. Which one of these may be expected to have the highest second ionization enthalpy ?$ (1) $Cr$ (2) $Mn$ (3) $Fe$ (4) $V$ 130. $The yellow colour of chromate ion and orange colour of dichromate ion is due to$ (1) $d - d transition only$ (2) $charge transfer only$ (3) $both d - d transition and charge transfer$ (4) $s - d transitions only$ 131. $In the standardization of N a_{2} S_{2} O_{3} using K_{2} C r_{2} O_{7} by iodometry, the equivalent weight of K_{2} C r_{2} O_{7} is$ (1) $(molecular weight)/2, (molar mass)/2$ (2) $(molecular weight)/6$ (3) $(molecular weight)/3$ (4) $same as molecular weight$ 132. $Which of the following combination will produce H_{2} gas ?$ (1) $Fe metal and conc. H N O_{3}$ (2) $Cu metal and conc. H N O_{3}$ (3) $Au metal and NaCN(aq) in the presence of air$ (4) $Zn metal and NaOH(aq)$ 133. $For the four successive transition elements (Cr, Mn, Fe and Co), the stability of + 2 oxidation state will be there in which of the following order$ (1) $M n > F e > C r > C o$ (2) $F e > M n > C o > C r$ (3) $C o > M n > F e > C r$ (4) $C r > M n > C o > F e (At. nos.$ 134. $Which of the following statement is not correct$ (1) $La (O H)_{3} is less basic than Lu (O H)_{3} .$ (2) $In lanthanide series ionic radius of L n^{+ 3} ion decreases.$ (3) $La is actually an element of transition series rather lanthanides.$ (4) $Atomic radius of Zn and Hf are same because oflanthanide contraction.$ 135. $Choose the correct statements from the following A. Mn_{2} O_{7} is an oil at room temperature B. V_{2} O_{4} reacts with acid to give VO_{2}^{2 +} C. CrO is a basic oxide D. V_{2} O_{5} does not react with acid Choose the correct answer from the options given below :$ (1) $A, B and D only$ (2) $A and C only$ (3) $A, B and C only$ (4) $B and C only$ 136. $How many protons will be consumed when dichromate ion oxidises Fe^{2 +} ions in aqueous acidic medium?$ (1) $4$ (2) $6$ (3) $10$ (4) $14$ 137. $The reason for greater range of oxidation states in actinoids is attributed to :$ (1) $The radioactive nature of actinoids$ (2) $Actinoid contraction$ (3) $5f, 6d and 7s levels having comparable energies$ (4) $4f and 5d levels being close in energies$ 138. $The catalyst used in the manufacture of polyethylene is a mixture of$ (1) $Ti, Al (CH_{3})_{3}$ (2) $Ti, CH_{3} MgBr$ (3) $TiCl_{3}, Si (CH_{3})_{4}$ (4) $TiCl_{4}, Al (CH_{3})_{3}$ 139. $Prolonged heating is avoided during the preparation of ferrous ammonium sulphate to$ (1) $Prevent hydrolysis$ (2) $Prevent reduction$ (3) $Prevent breaking$ (4) $Prevent oxidation$ 140. $The effect of lanthanoid contraction in the lanthanoid series of elements by and large means:$ (1) $increase in both atomic and ionic radii$ (2) $decrease in atomic radii and increase in ionic radii$ (3) $decrease in both atomic and ionic radii$ (4) $increase in atomic radii and decrease in ionic radii$ 141. $Which one of the following shows highest magnetic moment?$ (1) $Fe^{2 +}$ (2) $Co^{2 +}$ (3) $Cr^{3 +}$ (4) $Ni^{2 +}$ 142. $MnO_{4}^{2 -}, in acidic medium, disproportionates to :$ (1) $MnO4 -and MnO_{2}$ (2) $Mn_{2} O_{7} and MnO_{2}$ (3) $Mn_{2} O_{7} and MnO$ (4) $MnO_{4}^{-} and MnO$ 143. $Lanthanoid contraction is caused due to :$ (1) $the appreciable shielding on outer electrons by 4ƒ electrons from the nuclear charge$ (2) $the appreciable shielding on outer electrons by 5ƒ electrons from the nuclear charge$ (3) $the same effective nuclear charge from Ce to Lu$ (4) $the imperfect shielding on outer electrons by 4f electrons from the nuclear charge$ 144. $Amongst the following identify the species with an atom in +6 oxidation state.$ (1) $MnO_{4}^{-}$ (2) $Cr(CN)_{6}^{3-}$ (3) $NiF_{6}^{2-}$ (4) $C r O_{2} C l_{2}$ 145. $Which of the following statement concerning lanthanide elements is false$ (1) $All lanthanides are highly dense metals.$ (2) $More characteristic oxidation state of lanthanide elements is + 3.$ (3) $Lanthanides are separated from one another by ion exchange method.$ (4) $Ionic radii of trivalent lanthanides steadily increases with increase in the atomic number.$ 146. $The magnetic moment of a transition metal ion is 15 B.M. Therefore the number of unpaired electrons present in it is$ (1) $4$ (2) $1$ (3) $2$ (4) $3$ 147. $The ‘f’ orbitals are half and completely filled, respectively in lanthanide ions (Given: Atomic no. Eu, 63; Sm, 62; Tm, 69; Tb, 65; Yb, 70; Dy, 66]$ (1) $E u^{2 +} and T m^{2 +}$ (2) $S m^{2 +} and T m^{3 +}$ (3) $T b^{4 +} and Y b^{2 +}$ (4) $D y^{3 +} and Y b^{3 +}$ 148. $Without losing its concentration, Z n C l_{2} solution cannot be kept in contact with$ (1) $Pb$ (2) $Al$ (3) $Au$ (4) $Ag$ 149. $The lanthanide ion that would show colour is:$ (1) $G d^{3 +}$ (2) $S m^{3 +}$ (3) $L a^{3 +}$ (4) $L u^{3 +}$ 150. $Which of the following are correct? (i) V^{2 +} liberates hydrogen from a dilute acid (ii) The earlier members of lanthanide series behave more like aluminium (iii) The 'silver' UK coins are made of Cu / Ni alloy (iv) The maximum oxidation state exhibited by Neptunium is +7$ (1) $(i) (iii) only$ (2) $(ii) (iv) only$ (3) $(i) (iii) (iv) only$ (4) $(i) (ii) (iii) only$