Mole Concept – NEET 2026 Practice Test

Suppose the elements X and Y combine to form two compounds XY₂ and X₃Y₂. When 0.1 mole of XY₂ weighs 10 g and 0.05 mole of X₃Y₂ weighs 9 g, the atomic weights of X and Y are

What fraction of Fe exists as Fe(III) in Fe₀.₉₆O ? (Consider Fe₀.₉₆O to be made up of Fe(II) and Fe(III) only)

The percentage of C, H and N in an organic compound are 40%, 13.3% and 46.7% respectively then empirical formula is

A mixture of gases contains H₂ and O₂ gases in the ratio of 1 : 4 (w/w). What is the molar ratio of the two gases in the mixture ?

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 C is 12, H is 1)

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be

1.0 g of magnesium is burnt with 0.56 g O₂ in a closed vessel. Which reactant is left in excess and how much ? (At. wt. Mg = 24, O = 16)

The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s process is :

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

Oxidation numbers of A, B, C are +2, +5 and −2 respectively. Possible formula of compound is