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A Learning Portal from Recruitment India
Catalytic converters are generally made from
transition metals
alkaline metals
carbon
hydrogen
Answer with explanation
Answer: Option AExplanation
Catalytic converters are made from platinum or a similar, platinum-like metal, such as palladium or rhodium. A catalytic converter is an exhaust emission control device that reduces toxic gases and pollutants in exhaust gas from an internal combustion engine into less toxic pollutants by catalyzing a redox reaction (an oxidation or reduction reaction).
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Which one of the following is not a chemical change
Cracking of petroleum
Burning of coal in air
Fermentation of sugarcane juice
Crystallization of table salt from sea water
Answer with explanation
Answer: Option DExplanation
Crystallization of table salt from sea water
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Which one of the following materials contains calcium?
China clay
Corundum
Talc
Gypsum
Answer with explanation
Answer: Option DExplanation
Explanation:
Gypsum is known as calcium sulphate ..(Cas(o)4)..
It contains calcium about 23.3 %..
Rest of the options have not contains calcium..
So the correct answer is GYPSUM..
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Plaster of Paris is made up of
Cement
Gypsum
Marble
Limestone
Answer with explanation
Answer: Option BExplanation
Plaster of paris, quick-setting gypsum plaster consisting of a fine white powder (calcium sulfate hemihydrate), which hardens when moistened and allowed to dry.
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Which of the following phenomenon is considered responsible for Global Warming?
Fire in coal mines
Dry farming
Greenhouse effect
Monsoon
Answer with explanation
Answer: Option CExplanation
Modern global warming is the result of an increase in magnitude of the so-called greenhouse effect, a warming of Earth’s surface and lower atmosphere caused by the presence of water vapour, carbon dioxide, methane, nitrous oxides, and other greenhouse gases.
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Hydrogen bomb is based on the principle of
nuclear fusion
nuclear fission
artificial radioactivity
natural radioactivity
Answer with explanation
Answer: Option AExplanation
Hydrogen Bomb is based on the principle of Nuclear Fusion
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Which is also called Stranger Gas
Xenon
Neon
Argon
Nitrous oxide
Answer with explanation
Answer: Option AExplanation
Xenon, best known till a few years back as an inert gas filled inside incandescent lamps, is named after a Greek word, which means ‘stranger’. These days xenon, the rarest of the noble gases, is becoming increasingly familiar and is finding increased uses and usage in many fields.
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Which of the following is the essential element for batteries used in electric cars?
Magnesium
Lithium
Sodium
Bromine
Answer with explanation
Answer: Option BExplanation
The lithium-ion batteries needed to power electric cars use lithium carbonate or lithium hydroxide.
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Atomic number of an element is a more fundamental property than its atomic mass. Who among the following scientists has made the above statement?
Dmitri Mendeleev
Henry Moseley
J.J. Thomson
Ernest Rutherford
Answer with explanation
Answer: Option BExplanation
The scientist who first of all showed that the atomic number is more fundamental property of an element than its atomic mass was Henry Moseley. He is best known for the Moseley’s Law and contributions to Physics.
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The method that cannot be used for removing permanent hardness of water is
adding sodium carbonate
distillation
adding caustic sodaboiling
boiling
Answer with explanation
Answer: Option DExplanation
Permanent hardness of water cannot be removed by simple physical methods like boiling, filtering and distillation.
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A mixture of sand and naphthalene can be separated by
Fractional distillation
Sublimation
Chromatography
Any of them
Answer with explanation
Answer: Option BExplanation
Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state.
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The number of water molecules present in a drop of water (volume 0.0018 ml) at room temperature is
6.023 x 1019
1.568 x 103
4.84 x 1017
4.84 x 1017
Answer with explanation
Answer: Option AExplanation
At RT i.e. 25 C, the density of water is 1 g/L.
Mass of water = Density x volume = 1 g/L x 0.0018 x 10-3 L = 1.8 x 10-3 g
18 g water = 1 mole
1mole water contains 6.023 x 1023 molecules of water
So, 18 g water cotains 6.023 x 1023 molecules of water
Then, 1.8 x 10-3 g water contains 1.8 x 10-3 x 6.023 x 1023 / 18 g = 6.023 x 1019 molecules of water
===>> 6.023 x 1019
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Which of the following metals is in liquid state at normal room temperature?
Gallium
Radon
Silicon
Sodium
Answer with explanation
Answer: Option AExplanation
Gallium
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Gypsum is added to Cement so that, _________?
setting of cement can be fastened
setting of cement can be slowed
Cement strength can be improved
Cement strength can be controlled
Answer with explanation
Answer: Option BExplanation
setting of cement can be slowed.
Gypsum is a mineral and is hydrated calcium sulfate in chemical form. Gypsum plays a very important role in controlling the rate of hardening of the cement. During the cement manufacturing process, upon the cooling of the clinker, a small amount of gypsum is introduced during the final grinding process. Gypsum is added to control the “setting of cement”. If not added, the cement will set immediately after mixing water leaving no time for concrete placing.
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What are the number of moles of CO2 which contains 16 g of oxygen?
0.5 mole
0.2 mole
0.4 mole
0.25 mole
Answer with explanation
Answer: Option AExplanation
One mole of CO2 has mass of 44 g and 32 g of O2. So 16 g of O2 have 22 g of CO2 or 0.5 moles of it.
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