Elements and Metals Science MCQS 21 TO 40

            Elements and Metals Science MCQS 21 TO 40

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 & Explanation Answer: Option C

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22.	Galvanised iron sheets have a coating of
	A. lead B. chromium C. zinc D. tin Answer & Explanation Answer: Option C

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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 & Explanation Answer: Option C

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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 & Explanation Answer: Option A

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25.	Heavy water is
	A. deuterium oxide B. PH7 C. rain water D. tritium oxide Answer & Explanation Answer: Option A
26.	The chemical (ethyl mercaptan) added to the otherwise odourless LPG cooking gas for imparting a detectable smell to the gas is a compound of
	A. bromine B. fluorine C. chlorine D. sulphur Answer & Explanation Answer: Option D

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27.	The element common to all acids is
	A. hydrogen B. carbon C. sulphur D. oxygen Answer & Explanation Answer: Option A

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28.	Non stick cooking utensils are coated with
	A. Teflon B. PVC C. black paint D. polystyrene Answer & Explanation Answer: Option A

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29.	Monazite is an ore of
	A. titanium B. zirconium C. iron D. thorium Answer & Explanation Answer: Option D

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30.	Carbon, diamond and graphite are together called
	A. allotropes B. isomers C. isomorphs D. isotopes Answer & Explanation Answer: Option A

31.	Potassium nitrate is used in
	A. medicine B. fertiliser C. salt D. glass Answer & Explanation Answer: Option B

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32.	Permanent hardness of water may be removed by the addition of
	A. sodium carbonate B. alum C. potassium permanganate D. lime Answer & Explanation Answer: Option A

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33.	Soda water contains
	A. carbonic acid B. sulphuric acid C. carbon dioxide D. nitrous acid Answer & Explanation Answer: Option C

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34.	The most important ore of aluminium is
	A. galena B. calamine C. calcite D. bauxite Answer & Explanation Answer: Option D

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35.	Most soluble in water is
	A. camphor B. sulphur C. common salt D. sugar Answer & Explanation Answer: Option D

36.	Which of the following was to be discovered first in the chromospheres of the sun?
	A. Krypton B. Xenon C. Neon D. Helium Answer & Explanation Answer: Option D

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37.	Which of the following is in liquid form at room temperature?
	A. Lithium B. Sodium C. Francium D. Cerium Answer & Explanation Answer: Option C

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38.	Sodium metal is kept under
	A. petrol B. alcohol C. water D. kerosene Answer & Explanation Answer: Option D

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39.	Which of the following are the ingredients of gun metal?
	A. Iron, Zinc, Titanium B. Iron, tin C. Iron, Brass, Tin D. Copper, Tin Answer & Explanation Answer: Option D

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40.	From which mineral is radium obtained?
	A. Rutile B. Haematite C. Limestone D. Pitchblende Answer & Explanation Answer: Option D

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