When iron is placed in moist air, a reddish brown layer of hydrated iron (III) oxide (Fe2 O3 ) accumulates on its surface. This reddish brown layer is called:
A. iron
B. alloy
C. rust
D. dust
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Consider the following elements.
1. Cobalt
2. Phosphorus
3. Zinc
Which of the above elements are required for maintaining the healthy human body?
A. 1 and 2
B. 2 and 3
C. 1 and 3
D. 1, 2 and 3
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Which one of the following materials is very hard and very ductile?
A. Carborundum
B. Tungsten
C. Cast iron
D. Nichrome
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Match
List I with
List II .
List-I (Mineral)
List-II (Industries in which largely used)
a. Limestone
1. Cement
b. Copper
2. Electrical goods
c. Bauxite
3. Manufacture of aeroplanes
d. Manganese
4. Steel
A. a-1, b-2, c-3, d-4
B. a-2, b-3, c-4, d-1
C. a-3, b-4, c-1, d-2
D. a-4, b-1, c-2, d-3
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The corrosion of . . . . . . . . is a serious problem-
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When sodium sulphate solution is mixed with barium chloride solution,
A. There is no reaction
B. Sulphur dioxide is formed
C. Barium chloride is formed
D. Barium sulphate is formed
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Sodium is a reactive metal, which if kept open reacts with . . . . . . . . explode and catch fire.
A. Oxygen
B. Hydrogen
C. Nitrogen
D. Phosphorus
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Bronze is an alloy of . . . . . . . .
A. zinc and iron
B. copper and tin
C. tin and zinc
D. iron and mercury
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Which of the following metals gives yellow colour to flame when ignited?
A. sodium
B. potassium
C. calcium
D. barium
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Which of the following is flexible and soft?
A. sulphur
B. copper
C. carbon
D. phosphorus
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. . . . . . . . reacts more with water to form lime-
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Which of the following metals is used in photo films?
A. magnesium
B. silver
C. mercury
D. platinum
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The pair of compounds which cannot exist together in solution is
A. NaHCO3 and NaOH
B. NaHCO3 and H2 O
C. NaHCO3 and Na2 CO3
D. Na2 CO3 and NaOH
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Which of the following elements is not present in stainless steel?
A. iron
B. tungsten
C. chromium
D. nickel
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Find odd pair.
A. Nitrogen and oxygen ⟺ air
B. Sulphur and phosphorus ⟺ matchstick
C. Hydrogen and oxygen ⟺ water
D. Magnesium and Silver ⟺ Stainless Steel
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What is a quick silver?
A. Titanium
B. Mercury
C. Platinum
D. Radium
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In which of the following solutions MgCl2 is soluble?
A. Kerosene
B. Acetone
C. Petrol
D. Water
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Alum is an example of this.
A. Double salt
B. Table salt
C. Flak salt
D. Single salt
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Which metal is generally used for coating of brass utensils to prevent copper contamination?
A. Tin
B. Zinc
C. Aluminium
D. Lead
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Which of the following cannot be beaten into Sheets?
A. Gold
B. Silver
C. Potassium
D. Aluminium
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