TRANSITION ELEMENT QUIZ-7

Q1. Zinc, cadmium and mercury are:

•  f-block elements
•  s-block elements
•  p-block elements
•  d-block elements

Solution
The differentiating electrons enter the ns-orbital but they have configuration (n-1)d^10 ns^2.

Q2.Which pair of lanthanides is used in glass, blowers, goggles?

•  Np, Pu
•  Pu, Gd
•  Fm, Ho
•  Pr, Ho

Solution
B

Q3.  In order to refine “blister copper” it is melted in a furnace and is stirred with green logs of wood. The purpose is:

•   To expel the dissolved gases in the blister copper
•   To bring the impurities to surfaces and oxidise them
•  To increase the carbon content of copper
•  To reduce the metallic oxide impurities with hydrocarbon gases liberated from the wood

Solution
It is a reason for given fact.This involves auto reduction.

Q4. The final step in the metallurgical extraction of Cu metal from Cu pyrites takes place in a Bessemer converter. The reaction taking place is:

•  Cu_2 S+O_2⟶2Cu+SO_2
•  4Cu_2 O+FeS⟶8Cu+FeSO_4
•  Cu_2 S+2FeO⟶2CuO+2Fe+SO_2
•  2Cu_2 O+Cu_2 S⟶6Cu+SO_2

Solution
This involves auto reduction..

Q5.Magnetic moment of [Ag(CN)_2 ]^- is zero. How many unpaired electrons are there?

•  Zero
•  1
•  3
•  4

Solution
 Ag(CN)_2^- does not contain unpaired electrons

Q6. The alloy of steel that is used for making automobile parts and utensils is:Stainless steelNickel steelTungsten steel

•  Nickel steelTungsten steel
•  Stainless steelNickel steelTungsten steel
• Tungsten steel
•  Chromium steel

Solution
It is a fact.

Q7.Silver nitrate produces a black stain on skin due to:

•  Its corrosive action
•  Its strong reducing action
•  Its reduction to metallic silver
•  The formation of a complex compound

Solution
Ag^++e⟶Ag ; finely divided Ag is black in colour and thus.AgNO_3 causes black stain on skin. It is therefore, called lunar caustic.

Q8.When mercury (I) chloride is heated and the vapour so evolved are cooled, the substance on sublimation thus collected consists of

•  Mercury (II) chloride
•  Mercury and mercury (II) chloride
•  Mercury (I) and mercury (II) chloride
•  Mercury

Solution

Q9.Which metal is ferromagnetic?

•  Cr
•  Al
•  Zn
•  Fe

Solution
Fe is ferromagnetic, i.e., retains magnetic properties if field is removed

Q10. F_2 is formed by reacting K_2 MnF_6 with

•  KSbF_6
•  SbF_5
•  MnF_3
• MnF_4

Solution
K_2 MnF_6+2SbF_5→2KSbF_6+MnF_3+1/2 F_2 In this reaction, the stronger Lewis acid SbF_6 displaces the weaker one, MnF_4 from its salt. MnF_4 is unstable and readily decomposes to give MnF_3 and fluorine