41) In which among the following are the noble metals soluble?

a) Water gas
b) Aqua regia
c) H2_SO₄
d) NH₄OH

ANSWER : Aqua regia

42) Galvanization of iron sheets is done by:

a) Zn plating
b) Tin plating
c) Cu plating
d) Ag plating

ANSWER : Zn plating

43) Which metal is common between brass, bronze and German silver?

a) Zn
b) Al
c) Mg
d) Cu

ANSWER : Zn

44) What happens when NH4OH is added to a solution of copper sulphate?

a) Black precipitate of copper oxide is obtained.
b) Blue precipitate of copper hydroxide is obtained.
c) No change is observed
d) A deep blue solution is obtained.

ANSWER : A deep blue solution is obtained.

45) Coinage metals show the properties of:

a) Inert elements
b) Normal elements
c) Transitional elements
d) Typical elements

ANSWER : Transitional elements

46) In the reaction 3Zn + 2NH3 -> X + 3H₂. What is X ?

a) N₂ZnO₂

b) Zn (NO₃)₂

c) N₂ZnO₄

d) Zn₃N₂

ANSWER : Zn₃N₂

47) The method used for galvanisation of nuts, bolts, screws and washers is known as:

a) Sheradizing
b) Metallizing
c) Electro-galvanisation
d) Hot dipping

ANSWER : Sheradizing

48) ………….. of the transition metals usually exhibit highest oxidation states.

a) Iodides
b) Fluorides
c) Chlorides
d) Bromides

ANSWER : Fluorides

49) Zinc and mercury differs in showing variable valency like d – block elements because:

a) Their d – shells are complete
b) Their d – shells are incomplete
c) They are soft
d) They have only two electrons in the outermost shell.

ANSWER : Their d – shells are complete

50) Galvanization of iron denotes coating with:

a) Sn
b) Al
c) Zn
d) Cd

ANSWER : Zn  

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