CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 8 – The d-and f-Block Elements
Every year CBSE conducts board exams for 12th standard. These exams are very competitive to all the students. So our website provides online tests for all the 12th subjects. These tests are also very effective and useful for those who preparing for competitive exams like NEET, JEE, CA etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.
These online tests are based on latest CBSE Class 12 syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.
CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 8 – The d-and f-Block Elements
Question 1.
Which block of elements are known as transition elements?
(a) p-block
(b) s-block
(c) d-block
(d) f-block
Answer
Answer: (c) d-block
Question 2.
Which of the following is not an element of first transition series?
(a) Iron
(b) Chromium
(c) Magnesium
(d) Nickel
Answer
Answer: (c) Magnesium
Question 3.
The correct order of E\(_{0}^{M^{2+}/M}\) values with negative sign for the four successive elements Cr, Mn, Fe and Co is
(a) Fe > Mn > Cr > Co
(b) Cr > Mn > Fe > Co
(c) Mn > Cr > Fe > Co
(d) Cr > Fe > Mn > Co
Answer
Answer: (c) Mn > Cr > Fe > Co
Question 4.
Oxidation number of gold metal is
(a) +1
(b) 0
(c) -1
(d) all of these
Answer
Answer: (a) +1
Question 5.
Most abundant element in earth’s crust is
(a) Si
(b) Al
(c) Zn
(d) Fe
Answer
Answer: (a) Si
Question 6.
The number of unpaired electrons in gaseous species of Mn3+, Cl3+ and V3+ respectively are and the most stable species is
(a) 4, 3 and 2; V3+
(b) 3, 3 and 2; Cr3+
(c) 4, 3 and 2; Cr3+
(d) 3, 3 and 3; Mn3+
Answer
Answer: (c) 4, 3 and 2; Cr3+
Question 7.
Colour of transition metal ions are due to absorption of some wavelength. This results in
(a) d-s transition
(b) s-s transition
(c) s-t/transition
(d) d-d transition
Answer
Answer: (d) d-d transition
Question 8.
Which one of the following is diamagnetic ion?
(a) Co2+
(b) Ni2+
(c) Cu2+
(d) Zn2+
Answer
Answer: (d) Zn2+
Question 9.
Which group contains coloured ions out of the following?
1. Cu–. 2. Ti4- 3. Co2+ 4. Fe2-
(a) 1, 2, 3, 4
(b) 3, 4
(c) 2, 3
(4) 1, 2
Answer
Answer: (b) 3, 4
Question 10.
Shape of d-orbital is
(a) spherical
(b) dumb bell
(c) double dumb bell
(d) none of these
Answer
Answer: (c) double dumb bell
Question 11.
The melting points of Cu, Ag and Au follow the order
(a) Cu > Ag > Au
(b) Cu >Au > Ag
(c) Au > Ag > Cu
(d) Ag > Au > Cu
Answer
Answer: (b) Cu >Au > Ag
Question 12.
In which of the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other?
(a) Ti+, Ti3+
(b)Cu+, Cu3+
(c) Cr2+, Cr3+
(d) V2+, VO2+ (V4)
Answer
Answer: (a) Ti+, Ti3+
Question 13.
Which of the following pairs of ions have the same electronic configuration?
(a) Cu2+, Cr2+
(b) Fe3+, Mn2+
(c) Co3+, Ni3+
(d) Sc3+, Cr3+
Answer
Answer: (b) Fe3+, Mn2+
Question 14.
In the diehromateanion (Cr2O\(_{7}^{2-}\))
(a) all Cr – O bonds are equivalent
(b) 6 Cr – O bonds are equivalent
(c) 3 Cr – O bonds are equivalent
(d) no bonds in Cr2O\(_{7}^{2-}\) are equivalent
Answer
Answer: (b) 6 Cr – O bonds are equivalent
Question 15.
The melting point of copper is higher than that of zinc because
(a) copper has a bcc structure
(b) the atomic volume of copper is higher
(c) the electrons of copper are involved in metallic bonding
(d) the s as well as d electrons of copper are involved in metallic bonding
Answer
Answer: (c) the electrons of copper are involved in metallic bonding
Question 16.
Zr and Hf have almost equal atomic and ionic radii because of
(a) diagonal relationship
(b) lartthanoid contraction
(c) actinoid contraction
(d) belonging to the same group
Answer
Answer: (b) lartthanoid contraction
Question 17.
Fe3+ ion is more stable than Fe2+ ion because
(a) more the charge on the atom, more is its stability
(b) configuration of Fe2+ is 3d5 while Fe3+ is 3d5
(c) Fe2+ has a larger size than Fe3+
(d) Fe3+ ions are coloured hence more stable
Answer
Answer: (b) configuration of Fe2+ is 3d5 while Fe3+ is 3d5
Question 18.
Which of the following is not an amphoteric ion?
(a) Al3+
(b) Cr3+
(c) Fe3+
(d) Zn2+
Answer
Answer: (c) Fe3+
Question 19.
One mole of acidfied K2Cr3+O on reaction with excess KI will liberate ………….. mole(s) of I2.
(a) 6
(b) 1
(c) 7
(d) 2
Answer
Answer: (a) 6
Question 20.
What happens when potassium iodide reacts with acidic solution of potassium dichromate?
(a) It liberates iodine
(b) Potassium sulphate is formed
(c) Chromium sulphate is formed
(d) All the above products are formed
Answer
Answer: (d) All the above products are formed
Question 21.
The number of moles of KMnO4 that are needed to react completely with one mole of ferrous oxalate in acidic solution is
(a) 3/5
(b) 2/5
(c) 4/5
(d) 1
Answer
Answer: (a) 3/5
Question 22.
Lanthanoid contraction is due to increase in
(a) atomic number
(b) effective nuclear charge
(c) atomic radius
(d) valence electrons
Answer
Answer: (b) effective nuclear charge
Question 23.
Which one of the following is called green vitriol?
(a) FeSO4 7H2O
(b) CuSO4 5H2O
(c) CaSO4 2H2O
(d) None of these
Answer
Answer: (a) FeSO4 7H2O
Question 24.
Electronic configuration of alkaline earth element is
(a) ns2
(b) ns1
(c) np6
(d) ns0
Answer
Answer: (a) ns2
Question 25.
Acidified potassium dichromate reacts with potassium iodide and oxidises it to I2. What is the oxidation state of chromium in the products of the reaction?
(a) +4
(b) +6
(c) +3
(d) +2
Answer
Answer: (c) +3
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