D and F Block Elements MCQ Questions & Answers in Inorganic Chemistry | Chemistry
Learn D and F Block Elements MCQ questions & answers in Inorganic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
51.
In which of the following ions, the colour is not due to $$d-d$$ transition?
A
$${\left[ {Ti{{\left( {{H_2}O} \right)}_6}} \right]^{3 + }}$$
B
$${\left[ {Cu{{\left( {N{H_3}} \right)}_4}} \right]^{2 + }}$$
C
$${\left[ {Co{F_6}} \right]^{3 - }}$$
D
$$CrO_4^{2 - }$$
Answer :
$$CrO_4^{2 - }$$
In $$CrO_4^{2 - },Cr$$ is in +6 oxidation state and has $${d^0}$$ configuration. The colour is due to charge transfer and not due to $$d{\text{ - }}d$$ transition.
52.
Cerium $$\left( {Z = 58} \right)$$ is an important member of the lanthanoids. Which of the following statements about cerium is incorrect?
A
The $$ + 4$$ oxidation state of cerium is not known in solutions
B
The $$ + 3$$ oxidation state of cerium is more stable than the $$ + 4$$ oxidation state
C
The common oxidation states of cerium are $$ + 3$$ and $$ + 4$$
D
Cerium $$\left( {IV} \right)$$ acts as an oxidizing agent
Answer :
The $$ + 4$$ oxidation state of cerium is not known in solutions
The $$ + 4$$ oxidation state of cerium is also known in solution.
53.
When $$Cu$$ reacts with $$AgN{O_3}$$ solution, the reaction takes place is
B
Copper $$(I)$$ compounds are colourless except when colour results from charge transfer.
C
Copper $$(I)$$ compounds are diamagnetic.
D
$$C{u_2}S$$ is black.
Answer :
$$C{u_2}O$$ is colourless.
$$C{u_2}O$$ is red in colour.
55.
Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii? ( Numbers in the parenthesis are atomic numbers ).
A
$$Ti\left( {22} \right)\,{\text{and}}\,Zr\left( {40} \right)$$
B
$$Zr\left( {40} \right)\,{\text{and}}\,Nb\left( {41} \right)$$
C
$$Zr\left( {40} \right)\,{\text{and}}\,Hf\left( {72} \right)$$
D
$$Zr\left( {40} \right)\,{\text{and}}\,Ta\left( {73} \right)$$
Because of the lanthanoid contraction $$Zr$$ ( atomic radii 160 $$pm$$ ) and $$Hf$$ ( atomic radii 158 $$pm$$ ) have nearly same atomic radii.
Lanthanoids include the elements from lanthanum $$La(Z =57)$$ to lutetium $$Lu(Z = 71).$$ zirconium $$Zr(40)$$ belong to the second transition series $$(4d)$$ and $$Hf (72)$$ belongs to third transition series $$(5d).$$ Lanthanoid contraction is associated with the intervention of the $$4f$$ orbitals which are filled before the $$5d$$ -series of elements starts. The filling of $$4f$$ orbitals before $$5d$$ -orbitals results in regular decrease in atomic radii which compensates the expected increase in atomic size with increasing atomic number. As a result of this lanthanoid contraction, the elements of second and third transition series have almost similar atomic radii.
56.
In order to prepare one litre one normal solution of $$KMn{O_4},$$ how many grams of $$KMn{O_4}$$ are required, if the solution is to be used in acid medium for oxidation?
A
158 $$g$$
B
31.60 $$g$$
C
62.0 $$g$$
D
790 $$g$$
Answer :
31.60 $$g$$
In acidic medium,
$$\mathop {MnO_4^ - }\limits_{\left( {{\text{From}}\,{\text{KMn}}{{\text{O}}_4}} \right)} + 8{H^ + } + 5{e^ - } \to $$ $$M{n^{2 + }} + 4{H_2}O$$
Thus, eq. wt. of $$KMn{O_4}$$ in acidic medium $$ = \frac{{Mol.\,wt.}}{5} = \frac{{158}}{5} = 31.6$$
∴ $$1\,N$$ solution can be prepared by dissolving $$31.6\,g\,KMn{O_4}$$ in $$1\,L$$ solution.
57.
Match the column I with column II and mark the appropriate choice.
Column I (Property)
Column II (Metal)
a.
Element with highest second ionisation enthalpy
1.
$$Cr$$
b.
Element with highest third ionisation enthalpy
2.
$$Cu$$
c.
$$M$$ in $$M{\left( {CO} \right)_6}$$ is
3.
$$Zn$$
d.
Element with highest heat of atomisation
4.
$$V$$
A
a - 2, b - 3, c - 1, d - 4
B
a - 4, b - 3, c - 1, d - 2
C
a - 3, b - 1, c - 2, d - 4
D
a - 1, b - 2, c - 3, d - 4
Answer :
a - 2, b - 3, c - 1, d - 4
No explanation is given for this question. Let's discuss the answer together.
58.
Which of the following reactions is not correct?
59.
The most durable metal plating on iron to protect against corrosion is
A
nickel plating
B
tin plating
C
copper plating
D
zinc plating
Answer :
zinc plating
Zinc is commonly used for covering iron surfaces. The process of covering iron with zinc is called galvanisation. If some scratches occur on the protective zinc film on coated iron, even then iron will not be rusted. This is due to the fact that because of scratches, both zinc and iron get exposed to oxidation but zinc undergoes oxidation in preference to iron, because the reduction potential of zinc is less than the reduction potential of iron. So, zinc coating is the best and durable method for protection of iron.
60.
The oxidation state of chromium in the final product formed by the reaction between $$Kl$$ and acidified potassium dichromate solution is: