Q. A simplest formula of a compound contains $50 \%$ element $X$ (atomic mass $10 ) \& \,50 \%$ element $Y$ (atomic mass $20$ ) is:

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A

$X Y$

B

$XY _{2}$

C

$X _{2} Y$

D

$X _{2} Y _{3}$

Solution:

Element % by mass Atomic mass % / Atomic mass Simple ratio

X 50 10 $50/10 = 5$ $5/2.5 = 20$ 2

Y 50 20 $50/20=2.5$ $2.5/2.5 = 1$ 1

Simple formula $X_2Y$

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