Some Basic Concepts in Chemistry — practice questions

167 curated practice questions from Some Basic Concepts in Chemistry (Chemistry JEE Main, NTA Exams) — 46 medium, 109 easy, 12 hard. Every question includes the final answer free; step-by-step worked solutions with a free account.

• A solution is prepared by adding 2 g of "X" to 1 mole of water. Mass percent of "X" in the solution is (Jee Main 2023)
• What is the weight of oxygen required for the complete combustion of 2.8 kg of ethylene ?
• The number of molecules and moles in 2.8375 litres of O_ 2 at STP are respectively (Jee Main 2023)
• The volume of CO 2 obtained at N.T.P. on heating 200 g of 50% pure CaCO 3 :
• Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A)…
• An oxide of metal (M) has 40% by mass of oxygen. Metal M has atomic mass of 24 . The empirical formula of the oxide is
• 1 volume of gaseous compound consisting C, H, O on complete combustion in presence of 2.5 volume of O 2 gives 2 volume…
• Rearrange the following I to IV in order of increasing masses and choose the correct answer [At. wt. of N = 14 u, O =…
• An antifreeze mixture contains 40% ethylene glycol (C 2 H 6 O 2 ) by weight in the aqueous solution. If the density of…
• Insulin contains 3.4% sulphur. What will be the minimum molecular weight of insulin?
• Equal weights of zinc and iodine react together and the iodine is completely converted to ZnI 2 . What fraction by…
• Silicon carbide, is produced by heating SiO 2 and C to high temperatures according to the equation : SiO 2 (s) + 3C (s)…
• SO 2 Cl 2 on reaction with excess of water results into acidic mixture SO 2 Cl 2 + 2H 2 O → H 2 SO 4 + 2HCl 16 moles of…
• There are two common oxides of sulphur, one of which contains 50% O 2 by weight the other almost exactly 60%. The…
• Compound A contains 8.7% Hydrogen, 74% Carbon and 17.3% Nitrogen. The molecular formula of the compound is, Given…
• 10 mL of commercial H 2 O 2 solution of 11.2 volume strength completely reacts with 0.1 dm 3 aqueous H 2 S solution…
• Identify the correct order of acidic strengths of CO 2 , CuO, CaO, H 2 O?
• Percentage of Se in peroxidase anhydrous enzyme is 0.5% by weight (At.wt. = 78.4), then minimum molecular weight of…
• Using the rules for significant figures, the correct answer for the expression 0.02858 0.112 0.5702 will be (JEE Main…
• 4.35 g of a sample of pyrolusite (MnO 2 ) when heated with conc. HCl gave chlorine. The chlorine when passed through…
• The density of 'x' M solution ('X' molar) of NaOH is 1.12 g mL –1 , while in molality, the concentration of the…
• A metal chloride weighing 0.22 g required 0.51 g of AgNO 3 to precipitate chloride completely. The specific heat of…
• Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R Assertion A…
• Which of the following has the smallest number of molecules?
• If a rocket runs on a fuel (C 15 H 30 ) and liquid oxygen, the weight of oxygen required and CO 2 released for every…
• X and Y are two elements which form X 2 Y 3 and X 3 Y 4 . If 0.20 mol of X 2 Y 3 weights 32.0 g and 0.40 mol of X 3 Y 4…
• The number of moles of SO 2 Cl 2 in 13.5 g is :
• What is the mass ratio of ethylene glycol ( C _ 2 H _ 6 O _ 2 , molar mass = 62 g/mol) required for making 500 g of…
• Formula which represents a simple ratio of atoms different elements present in a molecule of the substance is called :
• Molality (m) of 3M aqueous solution of NaCl is: [Given: Density of solution = 1.25 g mL –1 , molar mass in g mol –1 Na…
• A sample of peanut oil weighing 1.5 is added to 25 mL of 0.5 M KOH, after saponification is complete, 8.50 mlLof 0.25…
• A 10 mg effervescent tablet containing sodium bicarbonate and oxalic acid releases 0.25 mL of CO 2 at T = 298.15 K and…
• Normality of a mixture of 30 mL of 1N H 2 SO 4 and 20 mL of 4N H 2 SO 4 is
• The number of moles of methane required to produce 11 g CO 2 (g) after complete combustion is: (Given molar mass of…
• The ratio of molecules of O 2 and N 2 in a gaseous mixture (if their ratio by weight is 1:4) is:
• Iron (III) oxide can be reduced with CO to form metallic iron as described by unbalanced chemical reaction Fe 2 O 3 +…
• 0.7 g of Na 2 CO 3 .xH 2 O were dissolved in water and the volume was made to 100 mL, 20 mL of this solution required…
• When 500.0 mL of 1.0 M LaCl 3 and 3.0 M NaCl are mixed. What is molarity of Cl – ion ?
• What weight of a metal of equivalent weight 12 will give 0.475 g of its chloride ?
• The mole fraction of a given sample of I 2 in is 0.2. The molality of I 2 in C 6 H 6 is
• 1.134g of trivalent metal displaced 4g of copper (At. wt. = 63.5) from a solution of copper sulphate. The atomic weight…
• 1L solution of NaOH contains 4.0 g of it. What shall be the difference between molarity and the normality ?
• What is the molarity of SO _ 4 ^ 2- ion in aqueous solution that contain 34.2 ppm of Al 2 (SO 4 ) 3 ? (Assume complete…
• SO 2 gas was prepared by (i) burning sulphur in oxygen, (ii) reacting sodium sulphite with dilute H 2 SO 4 and (iii)…
• 250 g solution of D-glucose in water contains 10.8% of carbon by weight. The morality (in m) of the solution is nearest…
• Two isotopes of Boron are found in the nature with atomic weight 10.01(l) and 11.01 (II). The atomic weight of natural…
• A 1 g of an element give A 2 g of its oxide. The equivalent mass of the element is:
• The notations of symbols for elements that we use today was started by:
• One mole of a mixture of CO and CO 2 requires exactly 20 gram of NaOH in solution for complete conversion of all the CO…
• Haemoglobin contains 0.34% of iron by mass. The number of Fe atoms in 3.3 g of haemoglobin is : (Given : Atomic mass of…
• 25 g of an unknown hydrocarbon upon burning produces 88 g of CO 2 and 9 g of H 2 O. This unknown hydrocarbon contains:
• One part of an element A combines with two parts of another element B. Six parts of the element C combine with four…
• When 100 ml of 1 M NaOH solution and 10 ml of 10 N H 2 SO 4 solution are mixed together, the resulting solution will be…
• If LPG cylinder contains mixture of butane and isobutane, then the amount of oxygen that would be required for…
• If 240 g of carbon is taken in a container to convert it completely to CO 2 but in industry it has been found that 280…
• If 9 moles of O 2 and 14 moles of N 2 are placed in a container and allowed to react according to the equation : 3O 2 +…
• The weight of molecule of the compound C 60 H 122 is
• H 2 S contains 5.88% hydrogen, H 2 O contains 11.11% hydrogen while SO 2 contains 50% sulphur. These figures illustrate…
• The major product of the following reaction is
• If potassium chlorate is 80% pure, then 48 g of oxygen would be produced from (atomic mass of K = 39)
• What volume of 0.232 N solution contains 3.17 milliequivalent of solute ?
• When a hydrocarbon A undergoes combustion in the presence of air, it requires 9.5 equivalents of oxygen and produces 3…
• Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason(R). Assertion (A)…
• If N A is Avogadro’s number then number of valence electrons in 4.2 g of nitride ions (N 3– ) is
• KOH (V 1 mL , xN) is mixed with NaOH (V 2 mL , yN) & treated with 0.1 N HCl. 100 mL of HCl is required for complete…
• An organic compound has 42.1% carbon, 6.4% hydrogen and the remainder is oxygen. If its molecular weight is 342, then…
• The percentage of P 2 O 5 in isolable from diammonium hydrogen phosphate (NH 4 ) 2 HPO 4 is:
• x g of Ag was dissolved in HNO 3 and the solution was treated with excess of NaCl when 2.87 g of AgCl was precipitated…
• The average molecular weight of a mixture of gas containing nitrogen and carbon dioxide is 36. The mixture contains 280…
• n g of substance X reacts with m g of substance Y to form p g of substance R and q g of substance S. This reaction can…
• One of the following combinations illustrate law of reciprocal proportions
• 30g of magnesium and 30g of oxygen are reacted, then the residual mixture contains
• 1 L of a normal solution is diluted to 2000 ml. The resulting normality is :
• 1.0 g of a monobasic acid when completely reacted with Mg gave 1.301 g of anhydrous Mg salt. Equivalent weight of acid…
• A sample of pure calcium weighing 1.35 g was quantitatively converted to 1.88 g of pure calcium oxide. Atomic mass of…
• Mole fraction of ethanol in ethanol - water mixture is 0.25 . Hence, percentage concentration of ethanol (C 2 H 6 O) by…
• Given that the abundances of isotopes 54 Fe, 56 Fe and 57 Fe are 5%, 90% and 5%, respectively , the relative atomic…
• What volume of 0.4 M FeCl 3 . 6H 2 O will contain 600 mg of Fe 3+ ?
• Determine the empirical formula of Kelvar, used in making bullet proof vests, is 70.6% C, 4.2% H, 11.8% N and 13.4% O :
• 1.0 g of H 2 O 2 solution containing X% H 2 O 2 by weight requires X mL of KMnO 4 for complete oxidation in acid…
• Which of the following data illustrated the law of conservation of mass?
• Hydrogen combines with chlorine to form HCl. It also combines with sodium to form NaH. If sodium and chlorine also…
• A 5.82 g silver coin is dissolved in nitric acid. When sodium chloride is added to the solution all the silver…
• Major product of the following reaction is
• Given below are two statements. One is labelled as Assertion and the other is labelled as Reason. Assertion: Mass…
• 0.116 g of C 4 H 4 O 4 (A) is neutralised by 0.074 g of Ca(OH) 2 . Hence, protonic hydrogen ( H ^ ) in (A) will be
• The number of oxygen atoms present in 14.6 g of magnesium bicarbonate is:
• If 0.5 mol of BaCl 2 is mixed with 0.2 mol of Na 3 PO 4 , the maximum number of mole of Ba 3 (PO 4 ) 2 that can be…
• The volume of a solution containing HCl 73 g/litre would suffice for the exact neutralization of NaOH obtained by…
• A commercially sold conc. HCl is 35% HCl by mass. If the density of this commercial acid is 1.46 g/mL, the molarity of…
• 0.1 g of metal combines with 46.6 mL of oxygen at STP. The equivalent weight of metal is
• The volume equivalent of CO 2 in the reaction at NTP: NaHCO _ 3 + HCl NaCl + H _ 2 O + CO _ 2
• A sample of CaCO 3 has Ca = 40%, C = 12% and O = 48%. If the law of constant proportions is true, then the mass of Ca…
• 4.2 g of metallic carbonate MCO 3 was heated in a hard glass tube and CO 2 evolved was found to have 1120 mL of volume…
• Normality of solution obtained by mixing 10 mL of 1N HCl, 20 mL of 2N H 2 SO 4 and 30 mL of 3N HNO 3 is
• 0.765 g of an acid gives 0.535 g of CO 2 and 0.138 g of H 2 O. Then, the ratio of the percentage of carbon and hydrogen…
• Calculate the weight of lime (CaO) obtained by heating 200 kg of 95% pure lime stone (CaCO 3 )?
• 2.50 g sample of sodium bicarbonate when strongly heated gave 300 cm 3 of CO 2 measured at 27 ° and 760 mm pressure…
• A hydrate of Na 2 SO 3 losses 22.2% of H 2 O by mass on strong heating. The hydrate is
• An aqueous solution of ethanol has density 1.025 g/mL and it is 2 M. What is the molality of this solution ?
• Suppose the elements X and Y combine to form two compounds XY 2 and X 3 Y 2 . When 0.1 mole of XY 2 weighs 10 g and…
• 2IO 3 – + x I – + 12H + 6I 2 + 6H 2 O What is the value of x ?
• When 50 mL of 2.00 M HCl, 100 mL of 1.00 M HCl and 100 mL of 0.500 M HCl are mixed together, the resulting HCl…
• If 1 1 2 moles of oxygen combine with Al to form Al 2 O 3 , the weight of Al used in the reaction is (Al = 27)
• In gaseous reaction of the type aA + bB → cC + dD, which of the following is wrong?
• The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. This…
• 100 mL 5 14 M As 2 S 3 solution is reacted with 1 M KNO 3 solution. The volume of KNO 3 required is:
• An element with atomic mass Z consists of two isotopes of mass number Z - 1 and Z + 2. The percentage abundance of the…
• The number of water molecules present in a drop of water (volume = 0.0018 ml) at room temperature is (density of H 2 O…
• If a mixture containing 3 moles of hydrogen and 1 mole of nitrogen is converted completely into ammonia the ratio of…
• The reaction, 3ClO - (aq) → ClO 3 - (aq) + 2Cl - (aq) is an example of:
• 100 mL of 0.01 M metal-chloride completely hydrolysed in excess water, it has been observed that resulting solution…
• The weight of 60% H 2 SO 4 required to decompose 50 g of chalk (calcium carbonate) is:
• Match List I with List II List I List II A. 16 g of CH _ 4 (g) I. Weighs 28g B. 1 g of H_ 2 (g) II. 60.2 10^ 23…
• If 20% nitrogen is present in a compound, its minimum molecular weight can be
• The number of atoms contained in 11.2 L of SO 2 at N.T.P are:
• NH 3 is produced according to the following reaction : N 2 (g) + 3H 2 (g) → 2NH 3 (g) In an experiment 0.25 mol of NH 3…
• 120 g of an organic compound that contains only carbon and hydrogen give 330 g of CO 2 and 270 g of water on complete…
• The mass of CaO that shall be obtained by heating 20 kg of 90% pure lime-stone (CaCO 3 ) is
• Which of the following contains particles equal to those in 12 g Mg?
• Which of the following contains atoms equal to those in 12 g Mg ? (At. wt. Mg = 24)
• An oxide of the element contains 20% O 2 by weight. Calculate the equivalent weight of the element?
• What is the concentration of nitrate ions if equal volumes of 0.1 M AgNO 3 and 0.1 M NaCl are mixed together ?
• Molarity and Normality change with temperature because they involve :
• If water samples are taken from sea, river, clouds, lake or snow, they will be found to contain and O 2 in the…
• Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of…
• O _ g ~N _ 2 ( ~g ) +3 H _ 2 ( ~g ) 2 NH _ 3 ( ~g ) Consider the above reaction, the limiting reagent of the reaction…
• The carbonate of a metal is isomorphous (similar formula) with magnesium carbonate and contains 6.091 percent of…
• The number of iodine atoms present in 50 mL of a 0.1M KI solution is:
• Antimony reacts with sulphur according to the equation 2Sb(s) + 3S(s) → Sb 2 S 3 (s) The molar mass of Sb 2 S 3 is 340…
• Production of iron in blast furnace follows the following equation Fe 3 O 4 (s) + 4CO(g) → 3Fe(l) + 4CO 2 (g) When…
• 10 mL of 1 mM surfactant solution forms a monolayer covering 0.24 cm 2 on a polar substrate. If the polar head is…
• Cyclohexanol is dehydrated to cyclohexene on heating with conc. H 2 SO 4 . If the yield of this reaction is 75%, how…
• What is the weight % sulphuric acid in an aqueous solution which is 0.502 M in sulphuric acid ? The specific gravity of…
• M g of a substance when vaporised occupy a volume of 5.6 litre at NTP. The molecular mass of the substance will be :
• Consider the reaction 4HNO 3 (l) + 3KCl(s) → Cl 2 (g) + NOCl(g) + 2H 2 O(g) + 3KNO 3 (s) The amount of HNO 3 required…
• In a titration, 15.0 cm 3 of 0.100 M HCl neutralizes 30.0 cm 3 of Ca(OH) 2 . What is the molarity of Ca(OH) 2 solution ?
• The major product of the following reaction is
• NaOH is formed according to the reaction 2 Na + 1 2 O _ 2 Na _ 2 O Na _ 2 O + H _ 2 O 2 NaOH To make 4g of NaOH, Na…
• Out of the following the largest number of atoms are contained in:
• The number of atoms present in 0.5 mole of nitrogen gas is same as the atoms in
• Given the reaction Pb(NO 3 ) 2 (aq) + 2KI → PbI 2 (s) + 2KNO 3 (aq) What is the mass of PbI 2 that will precipitate if…
• Haemoglobin contains 0.33% of iron by weight. The molecular weight of haemoglobin is approximately 67200 . The number…
• 6.90 gm of metal carbonate were dissolved in 60 mL of 2N HCl. The excess acid was neutralized by 20 mL of 1N NaOH. What…
• 100 ml of 0.3 N HCl is mixed with 200 ml of 0.6 N H 2 SO 4 . The final normality of the resulting solution will be
• A sample of CaCO 3 and MgCO 3 weighed 2.21 g is ignited to constant weight of 1.152 g. The composition of mixture is…
• The mass of 112 cm 3 of CH 4 gas at STP is
• Which of the following have same number of significant figures? A. 0.00253 B. 1.0003 C. 15.0 D. 163 Choose the correct…
• The haemoglobin from red blood corpuscles of most mammals contain approximately 0.33% of iron by mass. The molecular…
• If AgBr is assumed to be completely insoluble, What mass of AgBr precipitates when 30.0 mL of a 0.500 mol/L solution of…
• The Ew of H 3 PO 4 in the reaction is Ca(OH) 2 + H 3 PO 4 → CaHPO 4 + 2H 2 O (Ca = 40, P = 31, O = 16)
• How many grams of phosphoric acid would be needed to neutralise 100 g of magnesium hydroxide ? (The molecular weights…
• A 1.50 g sample of an ore containing silver was dissolved, and all the Ag + was converted to 0.125 g Ag 2 S. What was…
• A compound possesses 8% sulphur by mass. The least molecular mass is:
• A sample of H 2 SO 4 (density 1.8 g mL –1 ) is 90% by weight. What is the volume of the acid that has to be used to…
• Which one is the best example of law of conservation of mass ?
• The volume of 0.02 M aqueous HBr required to neutralize 10.0 mL of 0.01 M aqueous Ba ( OH )_ 2 is (Assume complete…
• In which mode of expression, the concentration of a solution remains independent of temperature ?
• What is the empirical formula of a compound composed of O and Mn in equal weight ratio ?
• One mole of N 2 H 4 loses 10 moles of electron to form a new compound y. Assuming that all nitrogen appear in the new…
• 50 mL of 0.0535 M H 3 PO 4 was titrated with 0.115 M solution of NaOH to the end point identified by indicator X. This…
• Gastric juice contains 3.0 g of HCl per litre. If a person produces 2.5 litre of gastric juice per day, the number of…
• The Equivalent weight of an element is 13. It forms an acidic oxide which with KOH forms a salt isomorphous with K 2 SO…
• A sample of impure cuprite Cu 2 O contains 66.6% copper. What is the percentage of Cu 2 O in the sample:
• The weight of 11.2 litres of CO 2 at S.T.P. would be:
• How many grams of NaBr could be formed if 14.2 g of NaI are reacted with 40.0 mL of a 0.800 M Br 2 ? 2NaI + Br 2 →…
• 10 mL of 1 M BaCl 2 solution and 5 mL 0.5 M K 2 SO 4 are mixed together to precipitate out BaSO 4 . The moles of BaSO 4…

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