Some Basic Concepts of Chemistry

A compound X contains \(32\%\) of A , \(20\%\) of B and remaining percentage of C. Then, the empirical formula of X is
(Given atomic masses of \(\mathrm{A}=64\mathrm{u};\mathrm{B}=40\mathrm{u};\mathrm{C}=32\mathrm{u}\))

[NEET 2024]

The highest number of helium atoms is in

[NEET 2024]

If 200 ml of 0.1 M Na₂SO₄ is mixed with 200 ml of 0.2 M BaCl₂ solution. Total number of moles of all type of ions in the final solution is

On complete combustion, \(0.3 g\) of an organic compound gave \(0.2 g\) of \(CO _2\) and \(0.1 g\) of \(H _2 O\). The percentage composition of carbon and hydrogen in the compound, respectively are:

[Re-NEET 2024]

1 gram of sodium hydroxide was treated with \(25\mathrm{mL}\) of \(0.75\mathrm{M}\mathrm{HCl}\) solution, the mass of sodium hydroxide left unreacted is equal to

[NEET 2024]

Dalton's Atomic theory could not explain which of the following?

[NEET 2025]

1.0 g of \(H _2\) has same number of molecules as in

[Re-NEET 2024]

If 0.2 gram of an organic compound containing carbon, hydrogen and oxygen, on combustion yielded 0.147 grams of carbon dioxide and 0.12 grams of water. What will be the content of oxygen in the substance?

An ideal gaseous mixture of ethane (\({\mathrm{C}}_{2}{\mathrm{H}}_{6}\)) and ethene (\({\mathrm{C}}_{2}{\mathrm{H}}_{4}\)) occupies 28 liter at 1 atm and 273 K. The mixture reacts completely with 128 g \({\mathrm{O}}_{2}\)to produce \({\mathrm{CO}}_{2}\) and \({\mathrm{H}}_{2}\mathrm{O}\). The mole fraction at \({\mathrm{C}}_{2}{\mathrm{H}}_{6}\) in the mixture is:

When a hydrocarbon \(\mathrm{A}\) 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?

[JEE Main 2023, 29 Jan (Shift 2)]

Which one of the followings has maximum number of atoms?

[NEET 2020]

Match List-I with List-II.

Choose the correct answer from the options given below:

[JEE Main 2023, 10 Apr (Shift 2)]

One mole of carbon atom weighs \( 12 \mathrm{~g} \), the number of atoms in it is equal to (Mass of carbon- 12 is \( 1.9926 \times 10^{-23} \mathrm{~g} \) )

[Re-NEET 2020]

The correct option for the mass of \(\mathrm{CO}_2\) produced by heating \(20 \mathrm{~g}\) of \(20 \%\) pure limestone is
(Atomic mass of \(\mathrm{Ca}=40\)u)
\(\left[{\mathrm{CaCO}}_{3}\overset{1200\mathrm{K}}{\to }\mathrm{CaO}+{\mathrm{CO}}_{2}\right]\)

[NEET 2023]

An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of \( \mathrm{C} \) is \( 12, \mathrm{H} \) is 1\( ] \)

[NEET 2021]