Some Basic Concepts of Chemistry

317 Questions
2023 JEE Mains Numerical
JEE Main 2023 (Online) 8th April Morning Shift

$0.5 \mathrm{~g}$ of an organic compound $(\mathrm{X})$ with $60 \%$ carbon will produce __________ $\times 10^{-1} \mathrm{~g}$ of $\mathrm{CO}_{2}$ on complete combustion.

2023 JEE Mains Numerical
JEE Main 2023 (Online) 6th April Morning Shift

If 5 moles of $\mathrm{BaCl}_{2}$ is mixed with 2 moles of $\mathrm{Na}_{3} \mathrm{PO}_{4}$, the maximum number of moles of $\mathrm{Ba}_{3}\left(\mathrm{PO}_{4}\right)_{2}$ formed is ___________ (Nearest integer)

2023 JEE Mains Numerical
JEE Main 2023 (Online) 1st February Evening Shift

The molality of a $10 \%(\mathrm{v} / \mathrm{v})$ solution of di-bromine solution in $\mathrm{CCl}_{4}$ (carbon tetrachloride) is '$x$'. $x=$ ____________ $\times 10^{-2} ~\mathrm{M}$. (Nearest integer)

[Given : molar mass of $\mathrm{Br}_{2}=160 \mathrm{~g} \mathrm{~mol}^{-1}$

atomic mass of $\mathrm{C}=12 \mathrm{~g} \mathrm{~mol}^{-1}$

atomic mass of $\mathrm{Cl}=35.5 \mathrm{~g} \mathrm{~mol}^{-1}$

density of dibromine $=3.2 \mathrm{~g} \mathrm{~cm}^{-3}$

density of $\mathrm{CCl}_{4}=1.6 \mathrm{~g} \mathrm{~cm}^{-3}$]

2023 JEE Mains Numerical
JEE Main 2023 (Online) 1st February Morning Shift

The density of $3 \mathrm{M}$ solution of $\mathrm{NaCl}$ is $1.0 \mathrm{~g} \mathrm{~mL}^{-1}$. Molality of the solution is ____________ $\times 10^{-2} \mathrm{~m}$. (Nearest integer).

Given: Molar mass of $\mathrm{Na}$ and $\mathrm{Cl}$ is $23$ and $35.5 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively.

2023 JEE Mains Numerical
JEE Main 2023 (Online) 31st January Evening Shift
Assume carbon burns according to the following equation :

$2 \mathrm{C}_{(\mathrm{s})}+\mathrm{O}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{CO}(\mathrm{g})$

when $12 \mathrm{~g}$ carbon is burnt in $48 \mathrm{~g}$ of oxygen, the volume of carbon monoxide produced is ___________ $\times 10^{-1} \mathrm{~L}$ at STP [nearest integer]

[Given: Assume $\mathrm{CO}$ as ideal gas, Mass of $\mathrm{C}$ is $12 \mathrm{~g} \mathrm{~mol}^{-1}$, Mass of $\mathrm{O}$ is $16 \mathrm{~g} \mathrm{~mol}^{-1}$ and molar volume of an ideal gas at STP is $22.7 \mathrm{~L} \mathrm{~mol}^{-1}$ ]
2023 JEE Mains Numerical
JEE Main 2023 (Online) 31st January Evening Shift
A sample of a metal oxide has formula $\mathrm{M}_{0.83} \mathrm{O}_{1.00}$. The metal $\mathrm{M}$ can exist in two oxidation states $+2$ and $+3$.

In the sample of $\mathrm{M}_{0.83} \mathrm{O}_{1.00}$, the percentage of metal ions existing in $+2$ oxidation state is __________ $\%$. (nearest integer)
2023 JEE Mains Numerical
JEE Main 2023 (Online) 31st January Morning Shift

Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride. The volume of hydrogen gas produced at STP from the reaction of $11.5 \mathrm{~g}$ of zinc with excess $\mathrm{HCl}$ is __________ L (Nearest integer)

(Given : Molar mass of $\mathrm{Zn}$ is $65.4 \mathrm{~g} \mathrm{~mol}^{-1}$ and Molar volume of $\mathrm{H}_{2}$ at $\mathrm{STP}=22.7 \mathrm{~L}$ )

2023 JEE Mains Numerical
JEE Main 2023 (Online) 31st January Morning Shift

On complete combustion, $0.492 \mathrm{~g}$ of an organic compound gave $0.792 \mathrm{~g}$ of $\mathrm{CO}_{2}$. The % of carbon in the organic compound is ___________ (Nearest integer)

2023 JEE Mains Numerical
JEE Main 2023 (Online) 30th January Evening Shift

The strength of 50 volume solution of hydrogen peroxide is ______ $\mathrm{g} / \mathrm{L}$ (Nearest integer).

Given:

Molar mass of $\mathrm{H}_{2} \mathrm{O}_{2}$ is $34 \mathrm{~g} \mathrm{~mol}^{-1}$

Molar volume of gas at $\mathrm{STP}=22.7 \mathrm{~L}$
2023 JEE Mains Numerical
JEE Main 2023 (Online) 30th January Morning Shift

Some amount of dichloromethane $\left(\mathrm{CH}_{2} \mathrm{Cl}_{2}\right)$ is added to $671.141 \mathrm{~mL}$ of chloroform $\left(\mathrm{CHCl}_{3}\right)$ to prepare $2.6 \times 10^{-3} \mathrm{M}$ solution of $\mathrm{CH}_{2} \mathrm{Cl}_{2}(\mathrm{DCM})$. The concentration of $\mathrm{DCM}$ is ___________ ppm (by mass).

Given :

atomic mass : C = 12

H = 1

Cl = 35.5

density of $\mathrm{CHCl}_{3}=1.49 \mathrm{~g} \mathrm{~cm}^{-3}$

2023 JEE Mains Numerical
JEE Main 2023 (Online) 29th January Evening Shift

The volume of HCl, containing 73 g L$^{-1}$, required to completely neutralise NaOH obtained by reacting 0.69 g of metallic sodium with water, is __________ mL. (Nearest Integer)

(Given : molar masses of Na, Cl, O, H, are 23, 35.5, 16 and 1 g mol$^{-1}$ respectively.)

2023 JEE Mains Numerical
JEE Main 2023 (Online) 29th January Evening Shift

When 0.01 mol of an organic compound containing 60% carbon was burnt completely, 4.4 g of CO$_2$ was produced. The molar mass of compound is _____________ g mol$^{-1}$ (Nearest integer).

2023 JEE Mains Numerical
JEE Main 2023 (Online) 25th January Evening Shift

Number of hydrogen atoms per molecule of a hydrocarbon A having 85.8% carbon is __________

(Given : Molar mass of A = 84 g mol$^{-1}$)

2023 JEE Mains Numerical
JEE Main 2023 (Online) 25th January Morning Shift

In sulphur estimation, 0.471 g of an organic compound gave 1.4439 g of barium sulphate. The percentage of sulphur in the compound is ____________ (Nearest Integer)

(Given : Atomic mass Ba: 137 u, S: 32 u, O: 16 u)

2023 JEE Mains Numerical
JEE Main 2023 (Online) 24th January Evening Shift

The number of units, which are used to express concentration of solutions from the following is _________

Mass percent, Mole, Mole fraction, Molarity, ppm, Molality

2023 JEE Mains Numerical
JEE Main 2023 (Online) 24th January Morning Shift

When $\mathrm{Fe_{0.93}O}$ is heated in presence of oxygen, it converts to $\mathrm{Fe_2O_3}$. The number of correct statement/s from the following is ________

A. The equivalent weight of $\mathrm{Fe_{0.93}O}$ is ${{\mathrm{Molecular\,weight}} \over {0.79}}$

B. The number of moles of Fe$^{2+}$ and Fe$^{3+}$ in 1 mole of $\mathrm{Fe_{0.93}O}$ is 0.79 and 0.14 respectively

C. $\mathrm{Fe_{0.93}O}$ is metal deficient with lattice comprising of cubic closed packed arrangement of O$^{2-}$ ions

D. The % composition of Fe$^{2+}$ and Fe$^{3+}$ in $\mathrm{Fe_{0.93}O}$ is 85% and 15% respectively

2023 JEE Mains Numerical
JEE Main 2023 (Online) 24th January Morning Shift

5 g of NaOH was dissolved in deionized water to prepare a 450 mL stock solution. What volume (in mL) of this solution would be required to prepare 500 mL of 0.1 M solution? _____________

Given : Molar Mass of Na, O and H is 23, 16 and 1 g mol$^{-1}$ respectively

2022 JEE Mains Numerical
JEE Main 2022 (Online) 29th July Evening Shift

A 1.84 mg sample of polyhydric alcoholic compound 'X' of molar mass 92.0 g/mol gave 1.344 mL of $\mathrm{H}_{2}$ gas at STP. The number of alcoholic hydrogens present in compound 'X' is ________.

2022 JEE Mains Numerical
JEE Main 2022 (Online) 28th July Evening Shift

2L of 0.2M H2SO4 is reacted with 2L of 0.1M NaOH solution, the molarity of the resulting product Na2SO4 in the solution is _________ millimolar. (Nearest integer)

2022 JEE Mains Numerical
JEE Main 2022 (Online) 28th July Morning Shift

In the given reaction,

$X+Y+3 Z \leftrightarrows X YZ_{3}$

if one mole of each of $X$ and $Y$ with $0.05 \mathrm{~mol}$ of $Z$ gives compound $X Y Z_{3}$. (Given : Atomic masses of $X, Y$ and $Z$ are 10, 20 and 30 amu, respectively.) The yield of $X YZ_{3}$ is _____________ g. (Nearest integer)

2022 JEE Mains Numerical
JEE Main 2022 (Online) 28th July Morning Shift

On complete combustion of $0.492 \mathrm{~g}$ of an organic compound containing $\mathrm{C}, \mathrm{H}$ and $\mathrm{O}$, $0.7938 \mathrm{~g}$ of $\mathrm{CO}_{2}$ and $0.4428 \mathrm{~g}$ of $\mathrm{H}_{2} \mathrm{O}$ was produced. The % composition of oxygen in the compound is ___________.

2022 JEE Mains Numerical
JEE Main 2022 (Online) 27th July Morning Shift

$20 \mathrm{~mL}$ of $0.02 \,\mathrm{M} \,\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ solution is used for the titration of $10 \mathrm{~mL}$ of $\mathrm{Fe}^{2+}$ solution in the acidic medium.

The molarity of $\mathrm{Fe}^{2+}$ solution is __________ $\times \,10^{-2}\, \mathrm{M}$. (Nearest Integer)

2022 JEE Mains Numerical
JEE Main 2022 (Online) 26th July Evening Shift

A $100 \mathrm{~mL}$ solution of $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{MgBr}$ on treatment with methanol produces $2.24 \mathrm{~mL}$ of a gas at STP. The weight of gas produced is _____________ mg. [nearest integer]

2022 JEE Mains Numerical
JEE Main 2022 (Online) 26th July Morning Shift

Chlorophyll extracted from the crushed green leaves was dissolved in water to make $2 \mathrm{~L}$ solution of Mg of concentration $48\, \mathrm{ppm}$. The number of atoms of $\mathrm{Mg}$ in this solution is $x \times 10^{20}$ atoms. The value of $x$ is ___________. (Nearest Integer)

(Given : Atomic mass of $\mathrm{Mg}$ is $24 \mathrm{~g} \mathrm{~mol}^{-1} ; \mathrm{N}_{\mathrm{A}}=6.02 \times 10^{23} \mathrm{~mol}^{-1}$ )

2022 JEE Mains Numerical
JEE Main 2022 (Online) 26th July Morning Shift

When 800 mL of 0.5 M nitric acid is heated in a beaker, its volume is reduced to half and 11.5 g of nitric acid is evaporated. The molarity of the remaining nitric acid solution is x $\times$ 10$-$2 M. (Nearest integer)

(Molar mass of nitric acid is 63 g mol$-$1)

2022 JEE Mains Numerical
JEE Main 2022 (Online) 25th July Evening Shift

56.0 L of nitrogen gas is mixed with excess hydrogen gas and it is found that 20 L of ammonia gas is produced. The volume of unused nitrogen gas is found to be _________ L.

2022 JEE Mains Numerical
JEE Main 2022 (Online) 25th July Evening Shift

A sample of 4.5 mg of an unknown monohydric alcohol, R-OH was added to methylmagnesium iodide. A gas is evolved and is collected and its volume measured to be 3.1 mL. The molecular weight of the unknown alcohol is __________ g/mol. [Nearest integer]

2022 JEE Mains Numerical
JEE Main 2022 (Online) 30th June Morning Shift

Blister copper is produced by reaction of copper oxide with copper sulphide.

2Cu2O + Cu2S $\to$ 6Cu + SO2

When 2.86 $\times$ 103 g of Cu2O and 4.77 $\times$ 103 g of Cu2S are used for reaction, the mass of copper produced is _____________ g. (nearest integer)

(Atomic mass of Cu = 63.5 a.m. u, S = 32.0 a.m. u, O = 16.0 a.m. u)

2022 JEE Mains Numerical
JEE Main 2022 (Online) 28th June Evening Shift

The complete combustion of 0.492 g of an organic compound containing 'C', 'H' and 'O' gives 0.793 g of CO2 and 0.442 g of H2O. The percentage of oxygen composition in the organic compound is ______________. (nearest integer)

2022 JEE Mains Numerical
JEE Main 2022 (Online) 27th June Evening Shift

116 g of a substance upon dissociation reaction, yields 7.5 g of hydrogen, 60 g of oxygen and 48.5 g of carbon. Given that the atomic masses of H, O and C are 1, 16 and 12, respectively. The data agrees with how many formulae of the following?

A. CH3COOH, B. HCHO, C. CH3OOCH3, D. CH3CHO

2022 JEE Mains Numerical
JEE Main 2022 (Online) 27th June Morning Shift

Two elements A and B which form 0.15 moles of A2B and AB3 type compounds. If both A2B and AB3 weigh equally, then the atomic weight of A is _____________ times of atomic weight of B.

2022 JEE Mains Numerical
JEE Main 2022 (Online) 26th June Evening Shift

CNG is an important transportation fuel. When 100 g CNG is mixed with 208 g oxygen in vehicles, it leads to the formation of CO2 and H2O and produces large quantity of heat during this combustion, then the amount of carbon dioxide, produced in grams is ____________. [nearest integer]

[Assume CNG to be methane]

2022 JEE Mains Numerical
JEE Main 2022 (Online) 26th June Evening Shift

The moles of methane required to produce 81 g of water after complete combustion is _____________ $\times$ 10$-$2 mol. [nearest integer]

2022 JEE Mains Numerical
JEE Main 2022 (Online) 26th June Morning Shift

On complete combustion 0.30 g of an organic compound gave 0.20 g of carbon dioxide and 0.10 g of water. The percentage of carbon in the given organic compound is _____________. (Nearest integer)

2022 JEE Mains Numerical
JEE Main 2022 (Online) 25th June Evening Shift

A protein 'A' contains 0.30% of glycine (molecular weight 75). The minimum molar mass of the protein 'A' is __________ $\times$ 103 g mol$-$1 [nearest integer]

2022 JEE Mains Numerical
JEE Main 2022 (Online) 25th June Morning Shift

The number of N atoms in 681 g of C7H5N3O6 is x $\times$ 1021. The value of x is (NA = 6.02 $\times$ 1023 mol$-$1) (Nearest Integer)

2022 JEE Mains Numerical
JEE Main 2022 (Online) 25th June Morning Shift

1 L aqueous solution of H2SO4 contains 0.02 m mol H2SO4. 50% of this solution is diluted with deionized water to give 1 L solution (A). In solution (A), 0.01 m mol of H2SO4 are added. Total m mols of H2SO4 in the final solution is ___________ $\times$ 103 m mols.

2022 JEE Mains Numerical
JEE Main 2022 (Online) 25th June Morning Shift

Number of grams of bromine that will completely react with 5.0 g of pent-1-ene is ___________ $\times$ 10$-$2 g. (Atomic mass of Br = 80 g/mol) [Nearest Integer]

2022 JEE Mains Numerical
JEE Main 2022 (Online) 24th June Morning Shift

A 0.166 g sample of an organic compound was digested with conc. H2SO4 and then distilled with NaOH. The ammonia gas evolved was passed through 50.0 mL of 0.5 N H2SO4. The used acid required 30.0 mL of 0.25 N NaOH for complete neutralization. The mass percentage of nitrogen in the organic compound is ____________.

2021 JEE Mains Numerical
JEE Main 2021 (Online) 1st September Evening Shift
The number of atoms in 8g of sodium is x $\times$ 1023. The value of x is ____________. (Nearest integer)

[Given : NA = 6.02 $\times$ 1023 mol$-$1

Atomic mass of Na = 23.0 u]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 1st September Evening Shift
If 80 g of copper sulphate CuSO4 . 5H2O is dissolved in deionised water to make 5L of solution. The concentration of the copper sulphate solution is x $\times$ 10$-$3 mol L$-$1. The value of x is _____________.

[Atomic masses Cu : 63.54u, S : 32u, O : 16u, H : 1u]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 31st August Evening Shift
Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is ______________ $\times$ 10$-$1 M. (Nearest integer) [Atomic mass : Na = 23.0, O = 16.0, H = 1.0]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 31st August Morning Shift
The molarity of the solution prepared by dissolving 6.3 g of oxalic acid (H2C2O4.2H2O) in 250 mL of water in mol L$-$1 is x $\times$ 10$-$2. The value of x is _____________. (Nearest integer) [Atomic mass : H : 1.0, C : 12.0, O : 16.0]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 27th August Evening Shift
100 g of propane is completely reacted with 1000 g of oxygen. The mole fraction of carbon dioxide in the resulting mixture is x $\times$ 10$-$2. The value of x is ____________. (Nearest integer)

[Atomic weight : H = 1.008; C = 12.00; O = 16.00]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 27th August Morning Shift
In Carius method for estimation of halogens, 0.2 g of an organic compound gave 0.188 g of AgBr. The percentage of bromine in the compound is ______________. (Nearest integer)

[Atomic mass : Ag = 108, Br = 80]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 26th August Evening Shift
100 mL of Na3PO4 solution contains 3.45 g of sodium. The molarity of the solution is _____________ $\times$ 10$-$2 mol L$-$1. (Nearest integer)

[Atomic Masses - Na : 23.0 u, O : 16.0 u, P : 31.0 u]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 26th August Morning Shift
An aqueous KCl solution of density 1.20 g mL$-$1 has a molality of 3.30 mol kg$-$1. The molarity of the solution in mol L$-$1 is ____________ (Nearest integer) [Molar mass of KCl = 74.5]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 27th July Evening Shift
2SO2(g) + O2(g) $\to$ 2SO3(g)

The above reaction is carried out in a vessel starting with partial pressure PSO2 = 250 m bar, PO2 = 750 m bar and PSO3 = 0 bar. When the reaction is complete, the total pressure in the reaction vessel is _______ m bar. (Round off of the nearest integer).
2021 JEE Mains Numerical
JEE Main 2021 (Online) 27th July Morning Shift
The density of NaOH solution is 1.2 g cm$-$3. The molality of this solution is _____________ m. (Round off to the Nearest Integer)

[Use : Atomic mass : Na : 23.0 u, O : 16.0 u, H : 1.0 u, Density of H2O : 1.0 g cm$-$3]
2021 JEE Mains Numerical
JEE Main 2021 (Online) 25th July Evening Shift
The number of significant figures in 0.00340 is ____________.