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The number of hydrogen atoms present in 5.4 g of urea is : (Given : Molar mass of urea : 60 g mol-1, NA : 6.022 × 1023 particles mol-1)
(2) 2.168 × 1023
Urea, NH2CONH2, has 4 H atoms per molecule.
Moles of urea = 5.460 = 0.09 mol
⇒ Moles of H atoms = 4 × 0.09 = 0.36 mol
∴ Number of H atoms = 0.36 × 6.022 × 1023 = 2.168 × 1023
Answer: (2)
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