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Some Basic Concepts of Chemistry — JEE Main & Advanced NSEC PYQs

60 previous year questions from Some Basic Concepts of Chemistry with answers and solutions. Numbered list, year tags, and one-tap solutions — built for serious JEE / NEET practice.

60 questionsNSECSolutions on every page
1

Among the following, number of oxygen atoms present is the maximum in

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Which of the following mixtures of water and H ₂ SO ₄ would have mass percentage of H ₂ SO ₄ close to 30 ?

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A 500 mL glass flask is filled at 298 K and 1 atm . pressure with three diatomic gases X, Y and Z . The initial volume ratio of the gases before mixing was 5: 3: 1 . The density of

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Lithium oxide ( Li ₂ O ; molar mass =30 ~g ~mol ⁻¹ ) is used in space shuttles to remove water vapour according to the following reaction Li ₂ O _ ( s ) + H ₂ O ( ~g ) 2 LiOH _ ( s

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Battery acid ( H ₂ SO ₄ ) has density 1.285 ~g ~cm ⁻³ 10.0 ~cm ^3 of this acid is diluted to 1 ~L . 25 .0 ~cm ^3 of this diluted solution requires 25.0 ~cm ^3 of 0.1 N sodium hydro

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Which one of the following statements is not correct about glucose? ( . molar mass of glucose .=180 ~g ~mol ⁻¹ )

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1.250 g of metal carbonate ( MCO ₃ ) was treated with 500 mL of 0.1 M HCl solution. The unreacted HCl required 50.0 mL of 0.500 M NaOH solution for neutralization. Identify the met

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Radius of Ar atom is 145 pm . The percentage volume occupied by an Ar atom at STP is

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'Iodine number' is the grams of iodine atoms (atomic mass =127 ~g ~mol ⁻¹ ) that can react completely with100 g of a vegetable oil. Iodine monochloride (ICl) is a reagent used to d

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Compound ' Y ' (molar mass =88.12 ~g ~mol ⁻¹ ) containing 54.52 % carbon, 9.17 % hydrogen and 36.31 % oxygen gives a reddish-brown precipitate in Fehling's test. ' Y ' is

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Myoglobin, (Mb), an oxygen storage protein, contains 0.34 % Fe by mass and in each molecule of myoglobin one ion of Fe is present. Molar mass of Mb ( g mol ⁻¹ ) is ( . Molar mass o

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Penicillamine is used in the treatment of arthritis. One molecule of penicillamine contains a single sulphur atom and the weight percentage of sulphur in penicillamine is 21.49 % .

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Which of the following statement/s is/are correct? I. Number of significant figures in 2345.100 is three II. 0.00787 rounded to two significant figures is written as 0.787 10⁻² III

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A common method to clean acid spills is to use Na ₂ CO ₃ (Molar mass 106 g ). If 50.0 mL of 0.75 M HCl is spilt on a wooden surface, the amount of Na ₂ CO ₃ required is

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A balance having a precision of 0.001 g was used to measure a mass of a sample of about 15 g . The number of significant figures to be reported in this measurement is

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Lipoic acid with the following structure is a growth factor required by many organisms. Percentages of ' S ' and ' O ' in lipoic acid respectively are (atomic masses of ' S ' and '

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Mercury is highly hazardous and hence its concentration is expressed in the units of ppb (micrograms of Hg present in 1 L of water). Permissible level of Hg in drinking water is 0.

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A mixture of sodium ( Na ) and potassium ( K ) metals weighing 32 g was reacted with water and the solution obtained could be neutralized with 517.3 mL of 1.0 M H ₂ SO ₄( aq ) . Th

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The results obtained by four students, each performing a set of four titrations with the same solution under identical conditions, are given below. If the expected titre value is 2

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If refractive index, density, pressure, volume, heat capacity and surface tension are represented respectively as , , P , V , Q and , the set that contains only intensive propertie

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When 0.805 g of the potassium salt ( CH ₂ )_ n ( COOK )₂ of a dibasic organic acid was reduced, 0.323 g of potassium was obtained. Molar mass of the acid is

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A student performed an experiment to determine the molecular formula of a given sample of hydrated copper (II) sulphate by weighing the sample before and after heating. The formula

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Sodium azide ( NaN ₃ ) is used in the airbag of cars. This is a safety device which inflates on an impact according to the reaction 2 NaN ₃ 2 Na +3 ~N ₂ An air bag of a particular

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At constant T and P , 5.0 ~L of SO ₂ are reacted with 3.0 L of O ₂ according to the following equation 2 SO ₂( ~g )+ O ₂( ~g ) 2 SO ₃( ~g ) The volume of the reaction mixture at th

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Number of moles of KClO ₃ that have to be heated to produce 1.0 L of O ₂( ~g ) at STP can be expressed as

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A fuel/oxidant system consisting of N , N -dimethylhydrazine ( CH ₃ )₂ NNH ₂ and N ₂ O ₄ (both liquids) is used in space vehicle propulsion. The liquid components are mixed stoichi

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An agriculturist wants to use different concentrations of phosphorus as a fertilizer using P ₄ O ₁₀ . The correct expression to calculate P from P ₄ O ₁₀ is

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Antacids are medicines that temporarily neutralize the acid in the stomach and prevent heartburns. The volume of an antacid syrup containing 2.9 g of Mg ( OH )₂ per 100 mL to be gi

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The analysis of three different binary oxides of bromine ( Br ) and oxygen ( O ) gives the following results: Compound Mass of O combined with 1.0 g of Br X 0.101 g Y 0.303 g Z 0.5

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Among the following numbers, the one in which all the zeros are significant is

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At constant T and P , 5.0 ~L of SO ₂ are reacted with 3.0 L of O ₂ according to the following equation 2 SO ₂( ~g )+ O ₂( ~g ) 2 SO ₃( ~g ) The volume of the reaction mixture at th

Olympiad workbook Solution View → 32

1.250 g of metal carbonate ( MCO ₃ ) was treated with 500 mL of 0.1 M HCl solution. The unreacted HCl required 50.0 mL of 0.500 M NaOH solution for neutralization. Identify the met

Olympiad workbook Solution View → 33

Battery acid ( H ₂ SO ₄ ) has density 1.285 ~g ~cm ⁻³ 10.0 ~cm ^3 of this acid is diluted to 1 ~L . 25 .0 ~cm ^3 of this diluted solution requires 25.0 ~cm ^3 of 0.1 N sodium hydro

Olympiad workbook Solution View → 34

Lithium oxide ( Li ₂ O ; molar mass =30 ~g ~mol ⁻¹ ) is used in space shuttles to remove water vapour according to the following reaction Li ₂ O _ ( s ) + H ₂ O ( ~g ) 2 LiOH _ ( s

Olympiad workbook Solution View → 35

A fuel/oxidant system consisting of N , N -dimethylhydrazine ( CH ₃ )₂ NNH ₂ and N ₂ O ₄ (both liquids) is used in space vehicle propulsion. The liquid components are mixed stoichi

Olympiad workbook Solution View → 36

Which of the following mixtures of water and H ₂ SO ₄ would have mass percentage of H ₂ SO ₄ close to 30 ?

Olympiad workbook Solution View → 37

Which one of the following statements is not correct about glucose? ( . molar mass of glucose .=180 ~g ~mol ⁻¹ )

Olympiad workbook Solution View → 38

A student performed an experiment to determine the molecular formula of a given sample of hydrated copper (II) sulphate by weighing the sample before and after heating. The formula

Olympiad workbook Solution View → 39

Sodium azide ( NaN ₃ ) is used in the airbag of cars. This is a safety device which inflates on an impact according to the reaction 2 NaN ₃ 2 Na +3 ~N ₂ An air bag of a particular

Olympiad workbook Solution View → 40

A 500 mL glass flask is filled at 298 K and 1 atm . pressure with three diatomic gases X, Y and Z . The initial volume ratio of the gases before mixing was 5: 3: 1 . The density of

Olympiad workbook Solution View → 41

Among the following, number of oxygen atoms present is the maximum in

Olympiad workbook Solution View → 42

Radius of Ar atom is 145 pm . The percentage volume occupied by an Ar atom at STP is

Olympiad workbook Solution View → 43

Number of moles of KClO ₃ that have to be heated to produce 1.0 L of O ₂( ~g ) at STP can be expressed as

Olympiad workbook Solution View → 44

'Iodine number' is the grams of iodine atoms (atomic mass =127 ~g ~mol ⁻¹ ) that can react completely with100 g of a vegetable oil. Iodine monochloride (ICl) is a reagent used to d

Olympiad workbook Solution View → 45

Compound ' Y ' (molar mass =88.12 ~g ~mol ⁻¹ ) containing 54.52 % carbon, 9.17 % hydrogen and 36.31 % oxygen gives a reddish-brown precipitate in Fehling's test. ' Y ' is

Olympiad workbook Solution View → 46

Myoglobin, (Mb), an oxygen storage protein, contains 0.34 % Fe by mass and in each molecule of myoglobin one ion of Fe is present. Molar mass of Mb ( g mol ⁻¹ ) is ( . Molar mass o

Olympiad workbook Solution View → 47

Which of the following statement/s is/are correct? I. Number of significant figures in 2345.100 is three II. 0.00787 rounded to two significant figures is written as 0.787 10⁻² III

Olympiad workbook Solution View → 48

A common method to clean acid spills is to use Na ₂ CO ₃ (Molar mass 106 g ). If 50.0 mL of 0.75 M HCl is spilt on a wooden surface, the amount of Na ₂ CO ₃ required is

Olympiad workbook Solution View → 49

The analysis of three different binary oxides of bromine ( Br ) and oxygen ( O ) gives the following results: Compound Mass of O combined with 1.0 g of Br X 0.101 g Y 0.303 g Z 0.5

Olympiad workbook Solution View → 50

A balance having a precision of 0.001 g was used to measure a mass of a sample of about 15 g . The number of significant figures to be reported in this measurement is

Olympiad workbook Solution View → 51

Lipoic acid with the following structure is a growth factor required by many organisms. Percentages of ' S ' and ' O ' in lipoic acid respectively are (atomic masses of ' S ' and '

Olympiad workbook Solution View → 52

Mercury is highly hazardous and hence its concentration is expressed in the units of ppb (micrograms of Hg present in 1 L of water). Permissible level of Hg in drinking water is 0.

Olympiad workbook Solution View → 53

Penicillamine is used in the treatment of arthritis. One molecule of penicillamine contains a single sulphur atom and the weight percentage of sulphur in penicillamine is 21.49 % .

Olympiad workbook Solution View → 54

A mixture of sodium ( Na ) and potassium ( K ) metals weighing 32 g was reacted with water and the solution obtained could be neutralized with 517.3 mL of 1.0 M H ₂ SO ₄( aq ) . Th

Olympiad workbook Solution View → 55

If refractive index, density, pressure, volume, heat capacity and surface tension are represented respectively as , , P , V , Q and , the set that contains only intensive propertie

Olympiad workbook Solution View → 56

The results obtained by four students, each performing a set of four titrations with the same solution under identical conditions, are given below. If the expected titre value is 2

Olympiad workbook Solution View → 57

Among the following numbers, the one in which all the zeros are significant is

Olympiad workbook Solution View → 58

When 0.805 g of the potassium salt ( CH ₂ )_ n ( COOK )₂ of a dibasic organic acid was reduced, 0.323 g of potassium was obtained. Molar mass of the acid is

Olympiad workbook Solution View → 59

An agriculturist wants to use different concentrations of phosphorus as a fertilizer using P ₄ O ₁₀ . The correct expression to calculate P from P ₄ O ₁₀ is

Olympiad workbook Solution View → 60

Antacids are medicines that temporarily neutralize the acid in the stomach and prevent heartburns. The volume of an antacid syrup containing 2.9 g of Mg ( OH )₂ per 100 mL to be gi

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