Question

The simplest formula of a compound containing 50% of element of X (atomic mass = 10) and 50% of element Y (atomic mass = 20) by weight is :
(A) XY
(B) X2Y
(C) XY3
(D) X2Y3

Answer 1

Answer:

In this we have to find empirical formula

So 50/10=5

And for y. 50/20=5/2

Dividing these value with 5/2

We get ratio

2:1

So simplest formula is X2Y

Answer 2

The correct answer is option (B)$\bold{\mathrm{X}_{2} \mathrm{Y}}$

To find:

The simplest formula for the given compound.

Solution:

We know that,  

The mole is the ratio of the “mass of an element” to the “atomic mass” of the same element.

Mole $=\frac{\ {mass} 3}{\text { atomic mass }} ………… (1)$

Therefore from equation (1) becomes, for element  X,

Mole (X)$\frac{50}{10}=5$

and for element Y,

Mole (Y) $=\frac{50}{20}=2.5$

Hence molar ratio of X: Y = 5:2.5 = 2:1

Hence, the “simplest formula” of the given compound = $\mathrm{X}_{2} \mathrm{Y}$