Question

The atomic mass of $A$ and $B$ are 20 g and 40 g respectively. If $X$ g of $A$ contains $Y$ atoms, then how many atoms does $2X$ g of $B$ contains:

• A. $X$
• B. $Y$
• C. $X+Y$
• D. $2Y$

Answer 1

The correct option is B $Y$

Given, the atomic weight of $A$ and $B$ are 20 g and 40 g respectively, also $X$ g of $A$ contain $Y$ atoms.
Therefore, the number of atoms present in $2X$ g of B $=2\times Y\times \frac{20}{40}=Y$.