Some Basic Concepts of Chemistry — JEE Main PYQs

10 mL of 2 M NaOH solution is added to 20 mL of 1 M HCl solution kept in a beaker. Now, 10 mL of this mixture is poured into a volumetric flask of 100 mL containing 2 moles of HCl and made the volume upto the mark with distilled water. The solution in this flask is :

Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is
Given : Molar mass of Mg is $24\mathrm{g}{\mathrm{mol}}^{-1}$.

The Molarity (M) of an aqueous solution containing 5.85 g of NaCl in 500 mL water is :
(Given : Molar Mass Na : 23 and Cl: 35.5 gmol⁻¹)

Choose the Incorrect Statement about Dalton's Atomic Theory

Ail organic compound has $42.1\%$ carbon, $6.4\%$ hydrogen and remainder is oxygen. If its molecular weight is 342 , then its molecular formula is :

The number of moles of methane required to produce $11\mathrm{g}{\mathrm{CO}}_2(\mathrm{g})$ after complete combustion is:
(Given molar mass of methane in $\mathrm{g}{\mathrm{mol}}^{-1}:16$)

The density of ' x ' M solution (' x ' molar) of NaOH is $1.12\mathrm{g}{\mathrm{mL}}^{-1}$. while in molality, the concentration of the solution is 3 m ( 3 molal). Then x is
(Given : Molar mass of NaOH is $40\mathrm{g}/\mathrm{mol}$ )

Molality ( m ) of 3 M aqueous solution of NaCl is: (Given : Density of solution $=1.25\mathrm{g}{\mathrm{mL}}^{-1}$, Molar mass in $\mathrm{g}{\mathrm{mol}}^{-1}$ : Na-23, Cl-35.5)

A solution is prepared by adding 1 mole ethyl alcohol in 9 mole water. The mass percent of solute in the solution is ____ (Integer Answer)
(Given: Molar mass in ${\text{g mol}}^{-1}$ Ethyl alcohol: 46, water: 18)

Combustion of glucose $({\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6)$ produces ${\mathrm{CO}}_2$ and water. The amount of oxygen (in g) required for the complete combustion of 900 g of glucose is:
[Molar mass of glucose in $\mathrm{g}{\mathrm{mol}}^{-1}=180$]

Molarity (M) of an aqueous solution containing xg of anhyd. ${\mathrm{CuSO}}_4$ in 500 mL solution at $32{}^{\circ }\mathrm{C}$ is $2\times 10^{-1}\mathrm{M}$. Its molality will be ____ $\times 10^{-3}\mathrm{m}$. (nearest integer).
[Given density of the solution …

Mass of methane required to produce 22 g of ${\mathrm{CO}}_2$ after complete combustion is ______ g.
(Given Molar mass in g mol⁻¹ $\mathrm{C}=12.0$, $\mathrm{H}=1.0$, $\mathrm{O}=16.0$)

10 mL of gaseous hydrocarbon on combustion gives 40 mL of ${\mathrm{CO}}_2(\mathrm{g})$ and 50 mL of water vapour. Total number of carbon and hydrogen atoms in the hydrocarbon is ____.

Consider the following reaction:
$3{\mathrm{PbCl}}_2+2({\mathrm{NH}}_4{)}_3{\mathrm{PO}}_4\to {\mathrm{Pb}}_3({\mathrm{PO}}_4{)}_2+6{\mathrm{NH}}_4\mathrm{Cl}$
If 72 mmol of ${\mathrm{PbCl}}_2$ is mixed with 50 mmol of $({\mathrm{NH}}_4{)}_3{\mathrm{PO}}_4$, then amount …

Volume of 3 M NaOH (formula weight $40\mathrm{g}{\mathrm{mol}}^{-1}$) which can be prepared from 84 g of NaOH is $\_\_\_\_$ $\times 10^{-1}{\mathrm{dm}}^3$.

9.3 g of aniline is subjected to reaction with excess of acetic anhydride to prepare acetanilide. The mass of acetanilide produced if the reaction is $100\%$ completed is $\_\_\_\_$ $\times 10^{-1}\mathrm{g}$.
(Given molar mass in $\mathrm{g}{\mathrm{mol}}^{-1}$ N: 14, O: 16, C: …

A solution of ${\mathrm{H}}_2{\mathrm{SO}}_4$ is $31.4\%{\mathrm{H}}_2{\mathrm{SO}}_4$ by mass and has a density of $1.25\mathrm{g}/\mathrm{mL}$. The molarity of the ${\mathrm{H}}_2{\mathrm{SO}}_4$ solution is ____ M (nearest integer)
[Given molar mass of …

Molality of $0.8\mathrm{M}{\mathrm{H}}_2{\mathrm{SO}}_4$ solution (density $1.06\mathrm{g}{\mathrm{cm}}^{-3}$ ) is ____ $\times 10^{-3}\mathrm{m}$.

If 50 mL of 0.5 M oxalic acid is required to neutralise 25 mL of NaOH solution, the amount of NaOH in 50 mL of given NaOH solution is _____ g.

Number of moles of methane required to produce $22\mathrm{g}{\mathrm{CO}}_{2(\mathrm{g})}$ after combustion is $\mathrm{x}\times 10^{-2}$ moles. The value of $x$ is

The mass of sodium acetate $\left({\mathrm{CH}}_3\mathrm{COONa}\right)$ required to prepare 250 mL of 0.35 M aqueous solution is ______ g. (Molar mass of ${\mathrm{CH}}_3\mathrm{COONa}$ is $82.02{\mathrm{g}\mathrm{mol}}^{-1}$)

A sample of ${\mathrm{CaCO}}_3$ and ${\mathrm{MgCO}}_3$ weighed 2.21 g is ignited to constant weight of 1.152 g . The composition of mixture is :
(Given molar mass in $\mathrm{g}{\mathrm{mol}}^{-1}$
${\mathrm{CaCO}}_3:100,{\mathrm{MgCO}}_3:84$ )

The molarity of 1 L orthophosphoric acid $({\mathrm{H}}_3{\mathrm{PO}}_4)$ having $70\%$ purity by weight (specific gravity $1.54\mathrm{g}{\mathrm{cm}}^{-3}$) is ____ M.
(Molar mass of ${\mathrm{H}}_3{\mathrm{PO}}_4=98\mathrm{g}{\mathrm{mol}}^{-1}$)

If a substance 'A' dissolves in solution of a mixture of ' B ' and ' C ' with their respective number of moles as ${\mathrm{n}}_{\mathrm{A}},{\mathrm{n}}_{\mathrm{B}}$ and ${\mathrm{n}}_{\mathrm{C}}$, mole fraction of C in the solution is:

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)

Which of the following have same number of significant figures ?
(A) 0.00253
(B) 1.0003
(C) 15.0
(D) 163

Choose the correct answer from the options given below

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: 3.1500 g of hydrated oxalic acid dissolved in water to make 250.0 mL solution will result in 0.1 M oxalic acid solution.
Reason R: Molar mass of hydrated oxalic acid …

0.5 g of an organic compound (X) with 60% carbon will produce ______ $\times 10^{-1}$ g of $\mathrm{CO}{}_2$ on complete combustion.

The number of molecules and moles in 2.8375 litres of ${\mathrm{O}}_2$ at STP are respectively

A solution of sugar is obtained by mixing 200 g of its $25\%$ solution and 500 g of its $40\%$ solution (both by mass). The mass percentage of the resulting sugar solution is ____. (Nearest integer)

A solution is prepared by adding 2g of " X " of 1 mole of water. Mass percent of " X " in the solution is :

The volume of hydrogen liberated at STP by treating 2.4 g of magnesium with excess of hydrochloric acid is ____ $\times 10^{-2}$ L.

Given: Molar volume of gas is 22.4 L at STP.
Molar mass of magnesium is $24{\mathrm{g}\mathrm{mol}}^{-1}$.

A metal chloride contains 55.0% of chlorine by weight. 100 mL vapours of the metal chloride at STP weigh 0.57 g. The molecular formula of the metal chloride is
(Given: Atomic mass of chlorine is 35.5 u)

An analyst wants to convert. 1 L HCl of $\mathrm{pH}=1$ to a solution of HCl of pH 2 . The volume of water needed to do this dilution is $\_\_\_\_$ mL. (Nearest Integer)

An organic compound gives 0.220 g of ${\mathrm{CO}}_2$ and 0.126 g of ${\mathrm{H}}_2\mathrm{O}$ on complete combustion. If the % of carbon is 24 then the % hydrogen is ______ $\times 10^{-1}$. (Nearest integer)

1 g of a carbonate $({\mathrm{M}}_2{\mathrm{CO}}_3)$ on treatment with excess HCl produces 0.01 mol of ${\mathrm{CO}}_2$. The molar mass of ${\mathrm{M}}_2{\mathrm{CO}}_3$ is ______ ${\mathrm{g}\mathrm{mol}}^{-1}$. (Nearest integer)

The density of 3 M solution of 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 Na and Cl is 23 and $35.5\mathrm{g}{\mathrm{mol}}^{-1}$ respectively.

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

Given : Molar Mass of $\mathrm{Na}$, $\mathrm{O}$ and H is 23, 16 and 1 …

Uracil is base present in RNA with the following structure. % of N in uracil is ______.

Given:
Molar mass …

The number of units, which are used to express concentration of solutions from the following is ____.
Mass percent, Mole, Mole fraction, Molarity, ppm, Molality.

The density of a monobasic strong acid (Molar mass 24.2 g mol ) is 1.21 kg L . The volume of its solution required for the complete neutralization of 25 mL of 0.24 M NaOH is ______ × $10^{-2}\mathrm{mL}$ (Nearest integer)

What is the mass ratio of ethylene glycol (C₂H₆O₂, molar mass = 62 g/mol) required for making 500 g of 0.25 molal aqueous solution and 250 mL of 0.25 molar aqueous solution ?

Number of hydrogen atoms per molecule of a hydrocarbon A having 85.8% carbon is ____
(Given : Molar mass of A $=84\mathrm{g}{\mathrm{mol}}^{-1}$ )

When a hydrocarbon A undergoes combustion in the presence of air, it requires 9.5 equivalents of oxygen and produces 3 equivalents of water. What is the molecular formula of A?

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

The volume of HCl, containing $73{\mathrm{g}\mathrm{L}}^{-1}$, required to completely neutralise NaOH obtained by reacting 0.69 g of metallic sodium with water, is
$\_\_\_\_$ mL. (Nearest Integer)
(Given: molar Masses of $\mathrm{Na}$, $\mathrm{Cl}$, $\mathrm{O}$, $\mathrm{H}$ are 23, 35.5, 16 and …

A 300 mL bottle of soft drink has $0.2\mathrm{M}{\mathrm{CO}}_2$ dissolved in it. Assuming ${\mathrm{CO}}_2$ behaves as an ideal gas, the volume of the dissolved ${\mathrm{CO}}_2$ at STP is ______ mL. (Nearest integer)

Given: At STP, molar volume of an ideal gas is …

Some amount of dichloromethane $\left(\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{l}}_2\right)$ is added to 671.141 mL of chloroform $\left(\mathrm{CHC}{\mathrm{l}}_3\right)$ to prepare a $2.6\times 10^{-3}m$ (molal) solution of $\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{l}}_2$ (DCM). The concentration of DCM is ______ ppm (by mass).

Given: Atomic …

The molality of a 10% (v/v) solution of di-bromine solution in ${\mathrm{CCl}}_4$ (carbon tetrachloride) is 'x'. $x=$ ______ $\times 10^{-2}$ M. (Nearest integer)
[Given: molar mass of ${\mathrm{Br}}_2=160{\mathrm{g}\mathrm{mol}}^{-1}$, atomic mass of C = $12{\mathrm{g}\mathrm{mol}}^{-1}$, atom …

When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of A ?