Hello!

Let

X=0.25 and Y=0.5

Now according to question

LET,         X:Y

0.25:0.5

25:50

1:2

XY2 is your Answer

Hello student!!

The relative number of atoms of elements, 'X' and Y in a compound is 0.25 and 0.5. The empirical formula of compound is as follow.
Given-
X : Y
0.25 : 0.5
i.e    25 : 50
1 : 2
Hence  XY2
The empirical formula of the compound is XY2

Let the empirical formula beXaYb

Atoms ofX=0.25X=0.25

Atoms ofY=0.5Y=0.5

% ofX=X=0.25/(0.25+0.5)100=330.25/(0.25+0.5)100=33%

% ofY=Y=0.5/(0.25+0.5)100=670.5/(0.25+0.5)100=67%

Simplest ratio of the two i. E. Empirical formula will be XY2.