Some Basic Concepts of Chemistry · Chemistry · JEE Advanced

Numerical

$\mathrm{H}_2 \mathrm{S}$ (5 moles) reacts completely with acidified aqueous potassium permanganate solution. In this reaction, the number of moles of water produced is $\mathbf{x}$, and the number of moles of electrons involved is $\mathbf{y}$. The value of $(\mathbf{x}+\mathbf{y})$ is ________.

JEE Advanced 2023 Paper 2 Online

The stoichiometric reaction of $516 \mathrm{~g}$ of dimethyldichlorosilane with water results in a tetrameric cyclic product $\mathbf{X}$ in $75 \%$ yield. The weight (in g) of $\mathbf{X}$ obtained is _______.

[Use, molar mass $\left(\mathrm{g} ~\mathrm{mol}^{-1}\right): \mathrm{H}=1, \mathrm{C}=12, \mathrm{O}=16, \mathrm{Si}=28, \mathrm{Cl}=35.5$ ]

JEE Advanced 2023 Paper 1 Online

The treatment of an aqueous solution of $3.74 \mathrm{~g}$ of $\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}$ with excess KI results in a brown solution along with the formation of a precipitate. Passing $\mathrm{H}_{2} \mathrm{~S}$ through this brown solution gives another precipitate $\mathbf{X}$. The amount of $\mathbf{X}$ (in $g$ ) is ___________.

[Given: Atomic mass of $\mathrm{H}=1, \mathrm{~N}=14, \mathrm{O}=16, \mathrm{~S}=32, \mathrm{~K}=39, \mathrm{Cu}=63, \mathrm{I}=127$ ]

JEE Advanced 2022 Paper 1 Online

In the chemical reaction between stoichiometric quantities of KMnO₄ and KI in weakly basic solution, what is the number of moles of I₂ released for 4 moles of KMnO₄ consumed?

JEE Advanced 2020 Paper 2 Offline

5.00 mL of 0.10 M oxalic acid solution taken in a conical flask is titrated against NaOH from a burette using phenolphthalein indicator. The volume of NaOH required for the appearance of permanent faint pink color is tabulated below for five experiments. What is the concentration, in molarity, of the NaOH solution?

Exp. No.	Vol. of NaOH (mL)
1	12.5
2	10.5
3	9.0
4	9.0
5	9.0

JEE Advanced 2020 Paper 1 Offline

The mole fraction of urea in an aqueous urea solution containing 900 g of water is 0.05. If the density of the solution is 1.2 g cm^$$-$$3, then molarity of urea solution is ................

(Given data : Molar masses of urea and water are 60 g mol^$$-$$1 and 18 g mol^$$-$$1, respectively)

JEE Advanced 2019 Paper 2 Offline

The amount of water produced (in g) in the oxidation of 1 mole of rhombic sulphur by conc. HNO₃ to a compound with the highest oxidation state of sulphur is ..............

(Given data : Molar mass of water = 18 g mol^$$-$$1)

JEE Advanced 2019 Paper 2 Offline

To measure the quantity of $$MnC{l_2}$$ dissolved in an aqueous solution, it was completely converted to $$KMn{O_4}$$ using the reaction,

$$MnC{l_2} + {K_2}{S_2}{O_8} + {H_2}O \to KMn{O_4} + {H_2}S{O_4} + HCl$$ (equation not balanced).

Few drops of concentrated $$HCl$$ were added to this solution and gently warmed. Further, oxalic acid ($$225$$ $$mg$$) was added in portions till the colour of the permanganate ion disappeared. The quantity of $$MnC{l_2}$$ (in mg) present in the initial solution is ____________.

(Atomic weights in $$g\,\,mo{l^{ - 1}}:Mn = 55,Cl = 35.5$$ )

JEE Advanced 2018 Paper 2 Offline

A compound H₂X with molar weight of 80g is dissolved in a solvent having density of 0.4 gml^–1 . Assuming no change in volume upon dissolution, the molality of a 3.2 molar solution is

JEE Advanced 2014 Paper 1 Offline

If the value of Avogadro number is 6.023 $$\times$$ 10²³ mol^-1 and the value of Boltzmann constant is 1.380 $$\times$$ 10^-23 J K^-1, then the number of significant digits in the calculated value of the universal gas constant is

JEE Advanced 2014 Paper 1 Offline

29.2 % (w/w) HCl stock solution has density of 1.25 g mL^-1 . The molecular weight of HCl is 36.5 g mol^-1 . The volume (mL) of stock solution required to prepare a 200 mL solution of 0.4 M HCl is

IIT-JEE 2012 Paper 1 Offline

The volume (in mL) of 0.1 M AgNO₃ required for complete precipitation of chloride ions present in 30 mL of 0.01 M solution of $$[Cr{({H_2}O)_5}Cl]C{l_2}$$, as silver chloride is close to ____________.

IIT-JEE 2011 Paper 2 Offline

A student performs a titration with different burettes and finds titre values of 25.2 mL, 25.25 mL, and 25.0 mL. The number of significant figures in the average titre value is

IIT-JEE 2010 Paper 1 Offline

Silver (atomic weight = 108 g mol^-1) has a density of 10.5 g.cm^-3. The number of silver atoms on a surface of area 10^-12 m² can be expressed in scientific notation as y $$\times$$ 10^x. The value of x is?

IIT-JEE 2010 Paper 2 Offline

2.68 $$\times$$ 10^-3 moles of a solution containing an ion Aⁿ⁺ require 1.61 $$\times$$ 10^-3 moles of $$MnO_4^-$$ for the oxidation of An⁺ to $$AO_3^-$$ in acid medium. What is the value of n?

IIT-JEE 1984

MCQ (More than One Correct Answer)

To check the principle of multiple proportions, a series of pure binary compounds $\left(\mathrm{P}_{\mathrm{m}} \mathrm{Q}_{\mathrm{n}}\right)$ were analyzed and their composition is tabulated below. The correct option(s) is(are)

Compound	Weight % of $\mathrm{P}$	Weight % of $\mathrm{Q}$
1	50	50
2	44.4	55.6
3	40	60

JEE Advanced 2022 Paper 2 Online

MCQ (Single Correct Answer)

Dissolving 120 g of urea (mol. wt. 60) in 1000 g of water gave a solution of density 1.15 g/mL. The molarity of the solution is

IIT-JEE 2011 Paper 1 Offline

Given that the abundances of isotopes ⁵⁴Fe, ⁵⁶Fe and ⁵⁷Fe are 5%, 90% and 5%, respectively, the atomic mass of Fe is :

IIT-JEE 2009 Paper 1 Offline

Consider a titration of potassium dichromate solution with acidified Mohr’s salt solution using diphenylamine as indicator. The number of moles of Mohr’s salt required per mole of dichromate is

IIT-JEE 2007 Paper 2 Offline

Which has maximum number of atoms?

IIT-JEE 2003 Screening

Mixture X = 0.02 mol of [Co(NH₃)₅SO₄]Br and 0.02 mol of [Co(NH₃)₅Br]SO₄ was prepared in 2 litre of solution.
1 litre of mixture X + excess AgNO₃ $$ \to $$ Y.
1 litre of mixture X + excess BaCl₂ $$ \to $$ Z
No. of moles of Y and Z are

IIT-JEE 2003 Screening

How many moles of electron weigh one kilogram?

IIT-JEE 2002 Screening

An aqueous solution of 6.3 g oxalic acid dihydrate is made up to 250ml. the volume of 0.1N NaOH required to completely neutralize 10ml of this solution is :

IIT-JEE 2001 Screening

In the standardization of Na₂S₂O₃ using K₂Cr₂O₇ by iodometry, the equivalent weight of K₂Cr₂O₇ is:

IIT-JEE 2001 Screening

The oxidation state of the most electronegative element in the products of the reaction. BaO₂ with dil. H₂SO₄ are

IIT-JEE 1991

Read the following statement and explanation and answer as per the options given below:

STATEMENT (S): In the titration of Na₂CO₃ with HCl using methyl orange indicator, the volume required at the equivalence point is twice that of the acid required using phenolphthalein indicator.

EXPLANATION (E): Two moles of HCl are required for the complete neutralization of one mole of Na₂CO₃

IIT-JEE 1991

In which mode of expression, the concentration of a solution remains independent of temperature?

IIT-JEE 1988

A molal solution is one that contains one mole of solute in

IIT-JEE 1986

If 0.50 mol of BaCl₂ is mixed with 0.20 mol of Na₃PO₄, the maximum amount of Ba₃(PO₄)₂ that can be formed is

IIT-JEE 1981

A gaseous mixture contains oxygen and nitrogen in the ratio of 1 : 4 by weight. Therefore the ratio of their no of molecules is

IIT-JEE 1979

The total number of electrons is one molecule of carbon dioxide is

IIT-JEE 1979

2.76 g of silver carbonate on being strongly heated yields a residue weighing

IIT-JEE 1979

The largest number of molecules is in

IIT-JEE 1979

27 g of Al will react completely with how many grams if oxygen?

IIT-JEE 1978

A compound was found to contain nitrogen and oxygen in the ratio 28 gm and 80 gm respectively. The formula of compound is

IIT-JEE 1978

Subjective

Calculate the molarity of water if it's density is 1000 kg/m³

IIT-JEE 2003

Hydrogen peroxide solution (20 ml) reacts quantitatively with a solution of KMnO₄ solution is just decolourised by 10 ml of MnSO₄ in neutral medium simultaneously forming a dark brown precipitate of hydrated MnO₂. The brown precipitated is dissolved in 10 ml of 0.2 M sodium oxalate under boiling condition in the presence of dilute H₂SO₄. Write the balanced equations involved in the reactions and calculate the molarity of H₂O₂.

IIT-JEE 2001

How many millilitres of 0.5 M H₂SO₄ are needed to dissolve 0.5 g of copper(II) carbonate?

IIT-JEE 1999

A plant virus is found to consist of uniform cylindrical particles of 150 Å in diameter and 5000 Å long. The specific volume of the virus is 0.75 cm³/g. If the virus is considered to be a single particle, find its molar mass.

IIT-JEE 1999

An aqueous solution containing 0.10 g KIO₃ (formula weight = 214.0) was treated with an excess of KI solution. The solution was acidified with HCl. The liberated I₂ consumed 45.0 mL of thiosulphate solution to decolourise the blue strach-iodine complex. Calculate the molarity of the sodium thiosulphate solution.

IIT-JEE 1998

A 3.00 g sample containing Fe₃O₄, Fe₂O₃ and an inert impure substance is treated with excess of KI solution in presence of dilute H₂SO₄. The entire iron is converted into Fe²⁺ along with the liberation of iodine. The resulting solution is diluted to 100 ml, A 20 ml of the diluted solution requires 11.0 ml of 0.5 M Na₂S₂O₃ solution to reduce the iodine present. A 50 ml of the diluted solution, after complete extraction of the iodine requires 12.80 ml of 0.25 M KMnO₄ solution in the dilute H₂SO₄ medium for the oxidation of Fe²⁺. Calculate the percentages of Fe₂O₃ and Fe₃O₄ in the original sample.

IIT-JEE 1996

8.0575 $$\times$$ 10^-2 kg of Glauber's salt is dissolved in water to obtain 1 dm³ of a solution of density 1077.2 kg.m^-3. Calculate the molarity, molality and mole fraction Na₂SO₄ in the solution.

IIT-JEE 1994

The composition of a sample of Wustite is Fe_0.93O_1.00 what percentage of the iron is present in the form of Fe(III)?

IIT-JEE 1994

Upon mixing 45.0 ml. of 0.25 M lead nitrate solution with 25.0 ml. of 0.10M chromic sulphate solution, precipitation of lead sulphate takes place. How many moles of lead sulphate are formed? Also, calculate the molar concentrations of the species left behind in the final solution. Assume that lead sulphate is completely insoluble.

IIT-JEE 1993

A 2.0 g sample of a mixture containing sodium carbonate, sodium bicarbonate and sodium suplphate is gently heated till the evolution of CO₂ ceases. The volume of CO₂ at 750 mm Hg pressure and at 298K is measured to be 123.9 ml. A 1.5g of the same sample requires 150 ml. of (M/10) HCl for complete neutralisation. Calculate the % composition of the components of the mixture.

IIT-JEE 1992

One gram of commercial AgNO₃ is dissolved in 50 ml. of water. It is treated with 50 ml. of a KI solution. The silver iodide thus precipitated is filtered off. Excess of KI in the filterate is titrated with (M/10) KIO₃ solution in presence of 6M HCl till all I^- ions are converted into ICl. It requires 50 ml. of (M/10) KIO₃ solution. 20 ml. of the same stock solution of KI requires 30 ml. of (M/10) KIO₃ under similar conditions. Calculate the percentage of AgNO₃ in the sample.
(Reaction : KIO₃ + 2KI + 6HCl $$\to$$ 3ICl + 3KCl + 3H₂O)

IIT-JEE 1992

A 1.0 g sample of Fe₂O₃ solid of 55.2% purity is dissolved in acid and reduced by heating the solution with zinc dust. The resultant solution is cooled and made upto 100.0 ml. An aliquot of 25.0 ml of this solution requires 17.0 ml of 0.0167M solution of an oxidant for titration. Calculate the number of electrons taken by the oxidant in the reaction of the above titration.

IIT-JEE 1991

A solution of 0.2 g of a compound containing Cu²⁺ and $$C_2O_4^{2-}$$ ions on titration with 0.02M $$KMnO_4$$ in presence of $$H_2SO_4$$ consumes 22.6 ml. of the oxidant. The resultant solution in neutralized with Na₂CO₃, acidified with dil. acetic acid and treated with excess KI. The liberated iodine requires 11.3 ml of 0.05M Na₂S₂O₃ solution for complete reduction.

Find out the molar ratio of Cu²⁺ to $$C_2O_4^{2-}$$ in the compound.Write down the balanced redox reactions involved in the above titrations.

IIT-JEE 1991

Calculate the molality of 1 litre solution of 93% H₂SO₄ (weight/volume). The density of the solution is 1.84 g/ml

IIT-JEE 1990

A solid mixture (5.0 g) consisting of lead nitrate and sodium nitrate was headed below 600^oC until the weight of the residue was constant. If the loss in weight 28.0 percent, find the amount of lead nitrate and sodium nitrate in the mixture.

IIT-JEE 1990

A mixture of H₂C₂O₄ (oxalic acid) and NaHC₂O₄ weighing 2.02 g was dissolved in water and solution made upto one litre. Ten millilitres of the solution required 3.0 ml. of 0.1 N sodium hydroxide solution for complete neutralization. In another experiment, 10.0 ml. of the same solution, in hot dilute sulphuric acid medium. require 4.0 ml. of 0.1 N potassium permanganate solution for complete reaction. Calculate the amount of H₂C₂O₄ and NaHC₂O₄ in the mixture.

IIT-JEE 1990

An equal volume of a reducing agent is titrated separately with 1M KMnO₄ in acid neutral and alkaline media. The volumes of KMnO₄ required are 20 ml. in acid 33.4 ml. neutral and 100 ml in alkaline media. Find out the oxidation state of manganese in each reduction product. Give the balanced equations for all three half reactions. Find out the volume of 1M K₂Cr₂O₇ consumed; if the same volume of the reducing agent is titrated in acid medium.

IIT-JEE 1989

A sugar syrup of weight 214.2 g contains 34.2 g of sugar (C₁₂H₂₂O₁₁). Calculate (i) molal concentration and (ii) mole fraction of sugar in the syrup

IIT-JEE 1988

A sample of hydrazine sulphate (N₂H₆SO₄) was dissolved in 100 ml. of water, 10 ml of this solution was reacted with excess of ferric chloride solution and warmed to complete the reaction. Ferrous ion formed was estimated and it required 20 ml of M/50 potassium permanganate solution. Estimate the amount of hydrazine sulphate in one litre of the solution.

Reaction:

4Fe³⁺ + N₂H₄ $$\to$$ N₂ + 4Fe²⁺ + 4H⁺

$$MnO_4^-$$ + 4Fe²⁺ + 8H⁺ $$\to$$ Mn²⁺ + 5Fe³⁺ + 4H₂O

IIT-JEE 1988

Five ml of 8N nitric acid, 4.8ml of 5N hydrochloric acid and a certain volume of 17M sulphuric acid are mixed together and made upto 2 litre. Thirty ml of this acid mixture neutralise 42.9 ml of sodium carbonate solution containing one gram of Na₂CO₃.10H₂O in 100 ml of water. Calculate the amount in gram of the sulphate ions in solution.

IIT-JEE 1985

4.08 g of a mixture of BaO and an unknown carbonate MCO₃ was heated strongly. The residue weighed 3.64 g. This was dissolved in 100 ml of 1 N HCl. The excess acid required 16 ml of 2.5 N NaOH solution for complete neutralization. Identify the metal M. (At wt. H = 1, C = 12, O = 16, Cl = 35.5, Ba = 138)

IIT-JEE 1983

The density of a 3 M Sodium thiosulphate solution (Na₂S₂O₃) is 1.25 g per ml. Calculate

(i) the percentage by weight of sodium thiosulphate,

(ii) the mole fraction of sodium thiosulphate and

(iii) the molalities of Na⁺ and $$S_2O_3^{-2}$$ ions

IIT-JEE 1983

Hydroxylamine reduces iron (III) according to the equation:

2NH₂OH + 4Fe³⁺ $$\to$$ N₂O(g) $$ \uparrow $$ + H₂O + 4Fe²⁺ + 4H⁺

Iron (II) thus produced is estimated by titration with a standard permanganate solution. The reaction is :

$$MnO_4^-$$ + 5Fe²⁺ + 8H⁺ $$\to$$ Mn²⁺ + 5Fe³⁺ + 4H₂O

A 10 ml sample of hydroxylamine solution was Diluted to 1 litre. 50 ml of this diluted solution was boiled with an excess of iron (III) solution. The resulting solution required 12 ml of 0.02 M KMnO₄ solution for complete oxidation of iron (II). Calculate the weight of hydroxylamine in one litre of the original solution. (H = 1, N = 14, O = 16, K =39, Mn = 55, Fe = 56)

IIT-JEE 1982

A 1.00 gm sample of H₂O₂ solution containing X percent H₂O₂ by weight requires X ml of a KMnO₄ solution for complete oxidation under acidic conditions. Calculate the normality of the KMnO₄ solution.

IIT-JEE 1981

(a) 1 litre of a mixture of CO and CO₂ is taken. This mixture is passed through a tube containing red hot charcoal. The volume now becomes 1.6 litre. The volumes are measured under the same conditions. Find the composition of the mixture by volume.

(b) A compound contains 28 percent of nitrogen and 72 percent of metal by weight. 3 atoms of metal combine with 2 atoms of N. Find the atomic weight of metal.

IIT-JEE 1980

A hydrocarbon contains 10.5 g of carbon per gram of hydrogen. 1 litre of the hydrocarbon at 127^oC and 1 atmosphere weighs 2.8 g. Find the molecular formula.

IIT-JEE 1980

A mixture contains NaCl and unknown chloride MCl.

(i) 1g of this is dissolved in water. Excess of acidified AgNO₃ solution is added to it. 2.567 g of white ppt is formed.

(ii) 1 g of original mixture is heated to 300^oC. Some vapours come out which are absorbed in acidified AgNO₃ solution, 1.341 g of white precipitate was obtained.

Find the molecular weight of unknown chloride.

IIT-JEE 1980

Find
(i) The total number of neutrons and
(ii) The total mass of neutron in 7 mg of ¹⁴C
(Assume that mass of neutron = mass of hydrogen atom)

IIT-JEE 1980