Question

Which one of the following is not an alloy of Aluminium?
(A) Magnalium
(B) Duralium
(C) German silver
(D) Aluminium bronze

Answer 1

Hint: As we know that alloys are metallic compounds which are made up of one or more metal or non-metal elements. It can also be defined as a solid solution of metal elements or a mixture of metallic phases of various elements. So here we have to tell which of the given compounds is not an alloy of aluminium metal that means one element must be aluminium metal for it to be an aluminium alloy.

Complete answer:
Let us first understand about alloys as follows:-
-Alloys: These are metallic compounds that are made up of one or more metal or non-metal elements. It can also be defined as a solid solution of metal elements or a mixture of metallic phases of various elements.
-These alloys are usually categorized as substitutional or interstitial alloys (based on the atomic arrangement which forms the alloy). These can be further classified as homogeneous, heterogeneous or intermetallic based on the phases of metal mixed in.
-Now let us check the composition of following alloys as follows:-
(A) Magnalium: It is an aluminium alloy that contains 5% magnesium (Mg) and 95% aluminum (Al) metal. It exhibits higher strength, greater corrosion resistance and also has lower density than that of pure aluminium.
(B) Duralium: It is also an alloy of aluminium along with copper (Cu), manganese (Mn) and magnesium (Mg) as the main metals in composition. It is used for manufacturing bicycle components and framesets.
(C) German silver: It is also known as nickel silver or Maillechort. It is an alloy of copper (Cu) with 20% nickel (Ni) and 20% zinc (Zn) metal. It has a silvery appearance. Since it does not contain aluminium as one of the components, therefore it is not an alloy of aluminium.
(D) Aluminium bronze: It is a type of bronze where the main alloying metal is aluminium. It is generally added to copper to form this alloy and other alloying agents are iron (Fe), manganese (Mn) and silicon (Si).

From the above data we can conclude that (C) German silver is not an alloy of Aluminium.

Note:
-Remember that German silver may be considered as an alloy of silver but it does not contain silver metal as any of its components. It is named so because of its silvery appearance.
-Also learn and understand the composition of alloys of common metals being used to answer such types of questions.