TRANSTION ELEMENT QUIZ-3

Q1. The element present in gun metal is

•  Co
•  Ti
•  Sc
•  Cu

Solution
Gun metal is an alloy of Cu, Sn and Zn. It is used to make cartridge of rifles and pistols.

Q2.How is limestone used in Fe extraction?

•  Oxidation of Fe ore
•  Formation of slag
•  Purification of Fe formed
•  Reduction of Fe ore

Solution
In Fe extraction limestone is used for the formation of slag. The central zone where the temperature varies from 800-1000°C; the lime-stone present in the charge decomposes into calcium oxide and carbon dioxide. CaO_3 □(→┴(1000°C) ) CaO+CO_2 The calcium oxide acts as flux and combines with silica present as an impurity to form a fusible slag of CaSiO_3. CaO+SiO_2⟶CaSiO_3

Q3.  In the metallurgy of iron, when limestone is added to the blast furnace, the calcium ion ends up as :

•   Calcium carbonate
•  Metallic calcium
•  Gangue
•  Slag

Solution

Q4. All metal chlorides are soluble in water except those of:

•  Ba, Sr, Li
•  Zn, Cu, Cd
•  Na, K, Ca
•  Ag, Pb, Hg

Solution
Chlorides of Ag, Pb and Hg are insoluble in water.

Q5.Which of the following may be colourless?

•  Cu^+
•  Cu^(2+)
•  Cr^(3+)
•  Fe^(3+)

Solution
 

Q6. Various methods have been employed for protecting iron from rusting. Which of the following is incorrect?

•  Zinc plating is more permanent than chrome plating
•  Zinc protects iron but gets corroded itself
• Tin plating is cheap but unreliable
•  None of the above

Solution
Zn does not show corrosion

Q7.Percentage of gold in 21.6 carat gold is:

•  70
•  10
•  90
•  21.6

Solution
24 carat gold means 100% Au

Q8.On the extraction of iron, the slag produced is

•  MgSiO_3
•  CaSiO_3
•  FeSiO_3
•  CO

Solution

Q9.Which metal is used for filament of electric bulb?

•  Fe
•  Cu
•  Pt
•  W

Solution
Tungsten filaments are used in bulbs.

Q10. Cl_2+HgO⟶?

•  Cl_2 O+HgCl
•  Cl_2 O+HgCl_2
•  ClO+HgCl
• ClO+HgCl_2

Solution