NEET Exam MCQs
Chemistry: Some Basic Concepts in Chemistry
Chemistry: Some Basic Concepts in Chemistry 37 Questions
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The number of significant figures for the three numbers 161 cm, 0.161 cm, 0.0161 cm are
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0.24 g of a volatile gas, upon vaporisation, gives 45 mL vapour at NTP. What will be the vapour density of the substance? (Density of H 0.089)
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The molecular weight of O2 and SO2 are 32 and 64 respectively. At 15°C and 150 mmHg pressure, 1 L of O2 contains ‘N ’ molecules. The number of molecules in 2L of SO2 under the same conditions of temperature and pressure will be
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An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is [At. wt. of C is 12, H is 1]
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The number of protons, neutrons and electrons in 71 175 Lu, respectively, are
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Suppose the elements X and Y combine to form two compounds XY2 and X Y3 2 . When 0.1 mole of XY 2 weighs 10 g and 0.05 mole of X Y3 2 weighs 9 g, the atomic weights of X and Y are
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An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be
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Boron has two stable isotopes, 10 B (19%) and 11B (81%). Calculate average atomic weight of boron in the periodic table.
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While extracting an element from its ore, the ore is grind and leached with dil. KCN solution to form the soluble product potassium argento- cyanide. The element is
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A metal oxide has the formula Z .2 3O It can be reduced by hydrogen to give free metal and water. 0.1596 g of the metal oxide requires 6 mg of hydrogen for complete reduction. The atomic weight of the metal is
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Which one of the followings has maximum number of atoms?
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In which case is the number of molecules of water maximum?
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How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO ?3 The concentrated acid is 70% HNO3 .
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The maximum number of molecules are present in
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Haemoglobin contains 0.33% of iron by weight. The molecular weight of haemoglobin is approximately 67200 g. The number of iron atoms (at. weight of Fe is 56) present in one molecule of haemoglobin are
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The number of moles of oxygen in 1 L of air containing 21% oxygen by volume, under standard conditions, is
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The percentage weight of Zn in white vitriol [ZnSO4 . 7H2O] ⋅ is approximately equal to (at. mass of Zn =65, S = 32, O = 16 and H= 1)
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The total number of valence electrons in 4.2 g of N3 − ion is (NA is the Avogadro’s number)
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At STP, the density of CCl4 vapour in g L/ will be nearest to
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The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s process is
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20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? (Atomic weight of Mg 24= )
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What is the mass of precipitate formed when 50 mL of 16.9% solution of AgNO 3 is mixed with 50 mL of 5.8% NaCl solution? (Ag 107.8, N =14, O =16, Na =23, Cl =35.5 )
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When 22.4 L of H2 ( g) is mixed with 11.2 L of Cl2 (g ) , each at STP, the moles of HCl(g ) formed is equal to
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1.0 g of magnesium is burnt with 0.56 g of oxygen in a closed vessel. Which reactant is left in excess and how much? (At. weight of Mg = 24, O = 16)
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10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be
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How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl?
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What volume of oxygen gas (O 2) measured at 0°C and 1 atm, is needed to burn completely 1L of propane gas (C3 H8 ) measured under the same conditions?
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Number of moles of MnO4 – required to oxidise one mole of ferrous oxalate completely in acidic medium will be
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The number of moles of KMnO4 that will be needed to react with one mole of sulphite ion in acidic solution is
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The number of moles of KMnO4 reduced by one mole of KI in alkaline medium is
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he mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is (at. mass of Al = 27)
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n Haber process 30L of dihydrogen and 30L of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of gaseous mixture under the aforesaid condition in the end?
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Which has maximum number of molecules?
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Assuming fully decomposed, the volume of CO2 released at STP on heating 9.85 g of BaCO3 (at. Mass of Ba 137= ) will be
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In the reaction, 4NH3 ( g) + 5O2 ( g) ⎯→ 4NO(g ) + 6H2 O(l) When 1 mole of ammonia and 1 mole of O2 are made to react to completion, then
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Liquid benzene (C6H6) burns in oxygen according to the equation: 2C6H6 (l) + 15O2 (g ) ⎯→ 12CO2 (g ) + 6H2O( g). How many litres of O2 at STP are needed to complete the combustion of 39 g of liquid benzene? (Mol. weight of O 32,2 = C H = 78)
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What is the weight of oxygen required for the complete combustion of 2.8 kg of ethylene?
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