General Knowledge - General Science

Exercise :: General Science - Elements and Metals

21. 

When an iron nail gets rusted, iron oxide is formed

A. without any change in the weight of the nail
B. with decrease in the weight of the nail
C. with increase in the weight of the nail
D. without any change in colour or weight of the nail

Answer: Option C

Explanation:

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22. 

Galvanised iron sheets have a coating of

A. lead
B. chromium
C. zinc
D. tin

Answer: Option C

Explanation:

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23. 

Among the various allotropes of carbon,

A. coke is the hardest, graphite is the softest
B. diamond is the hardest, coke is the softest
C. diamond is the hardest, graphite is the softest
D. diamond is the hardest, lamp black is the softest

Answer: Option C

Explanation:

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24. 

The group of metals Fe, Co, Ni may best called as

A. transition metals
B. main group metals
C. alkali metals
D. rare metals

Answer: Option A

Explanation:

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25. 

Heavy water is

A. deuterium oxide
B. PH7
C. rain water
D. tritium oxide

Answer: Option A

Explanation:

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