JEE Chemistry The D and F Block Elements MCQs Set C

Question. Which of the following lanthanoid element is steel hard in nature?
(a) Sm
(b) Eu
(c) Pm
(d) Ce

Answer: A

Question. What is the percentage of lanthanoid metal in mischmetall
(a) 95%
(b) 20%
(c) 90%
(d) 5%

Answer: A

Question. Which of the following is the use of mischmetall
(a) Both
(b) In lighter flint
(c) In bullets
(d) None of these

Answer: A

Question.  Which of the following statements are correct ?
(i) The maximum oxidation state of Mn with the oxygen is +VII while with fluorine is +IV.
(ii) Fluorine is more oxidizing in nature than oxygen.
(iii) Fluorine exhibit an oxidation state of –1.
(iv) Seven fluorine cannot be accommodated around Mn.
(a) (i), (ii), (iii) and (iv)
(b) (i) and (iv)
(c) (ii), (iii) and (iv)
(d) (i), (ii) and (iii)

Answer: A

Question.  Which of the following statements are correct ?
(i) Chromium has the highest melting point among the series 1 metals.
(ii) Number of unpaired electrons is greater in Cr than other elements of series 1.
(iii) In any row the melting point of transition metal increases as the atomic number increases.
(a) (i) and (ii)
(b) (i), (ii) and (iii)
(c) (i) and (iii)
(d) (ii) and (iii)

Answer: A

Question.  Read the following statements?
(i) Aqueous solutions formed by all ions of Ti arecolourless.
(ii) Aqueous solution of ferrous ions is green in colour.
(iii) Small size and presence of vacant d-orbitals make transition metal ions suitable for formation of complex compounds.
(iv) Catalytic action of transition metals involves the increase of reactant concentration at catalyst surface and weakening of the bonds in the reacting molecules.
Which of the following is the correct code for above statements?
(a) FTTT
(b) TFTT
(c) TFFT
(d) FFTT

Answer: A

Question.  Which of the following statements are correct?
(i) Interstitial compounds contain non-metal atoms trapped inside the metal crystal whereas alloys are homogeneous blend of metals.
(ii) Steel and bronze are alloys of transition and nontransition metals.
(iii) Some boride containing interstitial compounds are very hard comparable to that of diamond.
(iv) Interstitial compounds are chemically more reactive than parent metal.
(a) (i) and (iii)
(b) (ii) and (iii)
(c) (ii) and (iv)
(d) (i), (ii) and (iii)

Answer: A

Question.  Read the following statements.
(i) Chemistry of actinoids is complex in comparsion to chemistry of lanthanoids.
(ii) Ce⁴⁺ is very good reducing agent.
(iii) Eu²⁺ is a strong reducing agent.
(iv) Out of all lanthanides Ce,Pr,Nd,Dy and Ho shows +4 oxidation state.
Which of the following is the correct code for the statements above?
(a) TFTF
(b) FTTF
(c) FTFT
(d) TTFF

Answer: A

Question. Read the following statements?
(i) Only Pu show maximum oxidation state of +7 in actinoids.
(ii) M⁴⁺ ion of Th is the only diamagnetic M⁴⁺ ion of actinoid series.
(iii) Electrons present in the 5f orbitals of actinides can participate in bonding to a firm greater extent as compared to electrons present in 4f orbitals of lanthanides.
(iv) Magnetic properties of actinoids are more complex than lanthanoids
Which of the following is the correct code for the statements above?
(a) FTTT
(b) TFFT
(c) TFTT
(d) FFTT

Answer: A

Question. Which of the following statement(s) regarding Hf and Zr is/are correct
(i) Hf has greater density than Zr.
(ii) Lanthanoid contraction is responsible for such radii
(a) Both (i) and (ii) are correct
(b) Both (i) and (ii) are incorrect
(c) Statement (i) is correct only
(d) Statement (ii) is correct only

Answer: A

Question. Assertion : Magnetic moment values of actinides are lesser than the theoretically predicted values.
Reason : Actinide elements are strongly paramagnetic
(a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(b) Assertion is correct, reason is incorrect
(c) Assertion is incorrect, reason is correct
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Which one of the following transition metal ions shows magnetic moment of 5.92 BM?
(a) Mn²⁺
(b) Cr³⁺
(c) Ti³⁺
(d) Cu²⁺

Answer: A

Question. In the following salts the lowest value of magnetic moment is observed in
(a) MnSO₄. 4H₂O
(b) CuSO₄.5H₂O
(c) ZnSO₄.7H₂O
(d) None of these

Answer: A

Question. In which of the following pairs both the ions are coloured in aqueous solutions ?
(a) Ni²⁺, Ti³⁺
(b) Sc³⁺, Co²⁺
(c) Sc³⁺, Ti³⁺
(d) None of these

Answer: A

Question. Cuprous ion is colourless while cupric ion is coloured because
(a) cuprous ion has complete d-orbital and cupric ion has an imcomplete d-orbital
(b) both have unpaired electrons in the d-orbitals
(c) cuprous ion has incomplete d-orbital and cupric ion has a complete d-orbital
(d) both have half filled p-and d-orbitals

Answer: A

Question. Acidified K₂Cr₂O₇ solution turns green when Na₂SO₃ is added to it. This is due to the formation of
(a) Cr₂(SO₄)₃
(b) Cr₂(SO₃)₃
(c) CrSO₄
(d) None of these

Answer: A

Question. Which of the statements is not true?
(a) Na₂Cr₂O₇ is preferred over K₂Cr₂O₇ in volumetric analysis.
(b) K₂Cr₂O₇ solution in acidic medium is orange
(c) K₂Cr₂O₇ solution becomes yellow on increasing the pH beyond 7.
(d) None of these

Answer: A

Question. When a small amount of KMnO₄ is added to concentrated H₂SO₄, a green oily compound is obtained which is highly explosive in nature. Compound may be
(a) Mn₂O₇
(b) Mn₂O₃
(c) MnO₂
(d) None of these

Answer: A

Question. Identify the product and its colour when MnO₂ is fused with solid KOH in the presence of O₂.
(a) K₂MnO₄, dark green
(b) Mn₂O₃, brown
(c) MnO, colourless
(d) None of these

Answer: A

Question. Which of the following oxidising reaction of KMnO₄ occurs in acidic medium?
(i) Fe²⁺ (green) is converted to Fe³⁺ (yellow).
(ii) Iodide is converted to iodate.
(iii) Thiosulphate oxidised to sulphate.
(iv) Nitrite is oxidised to nitrate.
(a) (i) and (iv)
(b) (ii) and (iv)
(c) (i) and (iii)
(d) (iv) only

Answer: A

Question. Knowing that the chemistry of lanthanoids(Ln) is dominated by its + 3 oxidation state, which of the following statements is incorrect?
(a) Ln (III) compounds are generally colourless
(b) Ln (III) hydroxide are mainly basic in character
(c) The ionic size of Ln (III) decrease in general with increasing atomic number
(d) None of these

Answer: A

Question. The +3 ion of which one of the following has half filled 4f subshell?
(a) Gd
(b) La
(c) Lu
(d) Ac

Answer: A