JEE Main 2025 (Online) 8th April Evening Shift | Some Basic Concepts of Chemistry Question 1 | Chemistry

On combustion 0.210 g of an organic compound containing C, H and O gave 0.127 g H₂O and 0.307 g CO₂. The percentages of hydrogen and oxygen in the given organic compound respectively are:

7.55, 43.85

6.72, 53.41

6.72, 39.87

53.41, 39.6

JEE Main 2025 (Online) 3rd April Evening Shift

MCQ (Single Correct Answer)

-1

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 $24 \mathrm{~g} \mathrm{~mol}^{-1}$.

0.24 mg

235.7 g

2.444 g

236 mg

JEE Main 2025 (Online) 3rd April Evening Shift

MCQ (Single Correct Answer)

-1

In Dumas' method for estimation of nitrogen 0.4 g of an organic compound gave 60 mL of nitrogen collected at 300 K temperature and 715 mm Hg pressure. The percentage composition of nitrogen in the compound is (Given : Aqueous tension at $300 \mathrm{~K}=15 \mathrm{~mm} \mathrm{Hg}$ )

$15.71 \%$

$17.46 \%$

$7.85 \%$

$20.95 \%$

JEE Main 2025 (Online) 3rd April Morning Shift

MCQ (Single Correct Answer)

-1

Among $10^{-9} \mathrm{~g}$ (each) of the following elements, which one will have the highest number of atoms?

Element: $\mathrm{Pb}, \mathrm{Po}, \mathrm{Pr}$ and Pt