Directions : In the following question more than one of the answers given may be correct. Select the correct answer and mark it according to the code:
Number of atoms in 560 g of Fe (atomic mass\[56\text{ }g\text{ }mo{{l}^{-1}}\]) is (1) twice that of 70 g N (2) half that of 20 gH (3) half that of 70 gC (4) twice that of 40 g NA) 1, 2 and 3 are correct.
B) 1 and 2 are correct.
C) 2 and 4 are correct.
D) 1 and 3 are correct.
Correct Answer: B
Solution :
\[Number\text{ }of\text{ }atoms=\frac{mass}{atomic\,mass}\times {{N}_{0}}\] \[\therefore \]Number of atoms in \[560\text{ }g\text{ }Fe=\frac{560}{56}\times {{N}_{0}}\] \[=10\times {{N}_{0}}\] \[\therefore \] Number of atoms in \[70\text{ }g\text{ }N=\frac{70}{14}\times {{N}_{0}}\] \[=5\times {{N}_{0}}\] = half of 560 g Fe \[\therefore \]Number of atoms in\[20\text{ }g\text{ }H=\frac{20}{1}\times {{N}_{0}}\] \[=20\text{ }{{N}_{0}}\] \[\therefore \]Number of atoms in\[70\text{ }g\text{ }C=\frac{70}{12}\times {{N}_{0}}\] \[=6\times {{N}_{0}}\] \[\therefore \]Number of atoms in\[40\text{ }g\text{ }N=\frac{40}{14}\times {{N}_{0}}\] \[=3\times {{N}_{0}}\] \[\therefore \]Number of atoms in 560 g Fe \[=2\times \]no. of atoms in 70 g N \[=\frac{1}{2}\times \]no. of atoms in 20 g H.
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