Which of the following has maximum number of atoms? (a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CO4​

(a) 18 g of H2O

Explanation:

The molecule with great number of moles will have great number of atoms.

By observation, since all compounds have same mass, water has the least molcular mass

the product of the pressure and volume is also constant

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