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NEET CHEMISTRYSome Basic Concepts of ChemistryEasy

Question

The number of water molecules is maximum in:

A

18 molecules of water18\text{ molecules of water}

B

1.8 g of water1.8\text{ g of water}

C

18 g of water18\text{ g of water}

D

18 moles of water18\text{ moles of water}

Step-by-Step Solution

Let us calculate the number of molecules in each given option using the Avogadro constant (NA=6.022×1023N_A = 6.022 \times 10^{23}):

Option A: It contains exactly 1818 molecules of water.

Option B: Number of moles in 1.8 g1.8\text{ g} of water =MassMolar mass=1.818=0.1 moles= \frac{\text{Mass}}{\text{Molar mass}} = \frac{1.8}{18} = 0.1\text{ moles}. Number of molecules =0.1×NA= 0.1 \times N_A.

Option C: Number of moles in 18 g18\text{ g} of water =1818=1 mole= \frac{18}{18} = 1\text{ mole}. Number of molecules =1×NA= 1 \times N_A.

Option D: Number of molecules in 18 moles18\text{ moles} of water =18×NA= 18 \times N_A.

Comparing all the values, 18×NA18 \times N_A is the largest. Therefore, 18 moles of water18\text{ moles of water} contains the maximum number of water molecules.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Some Basic Concepts of Chemistry. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYSome Basic Concepts of Chemistrynumbermoleculesmaximum

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