Question

Two elements, X (Atomic mass 16) and Y (Atomic mass 14) combine to form compounds A, B and C. The ratio of different masses of Y which combines with fixed mass of X in A, B, and C is $1:3:5$. If 32 parts by mass of X combines with 84 parts by mass of Y in B, then in C 16 parts by mass of X will combine with

• A. 14 parts by mass of Y
• B. 42 parts by mass of Y
• C. 70 parts by mass of Y
• D. 82 parts by mass of Y

Answer 1

The correct option is C 70 parts by mass of Y

In compound B, 32 parts of X react with 84 parts of Y.
In compound C, 16 parts of X react with m parts of Y.
The ratio of masses of Y which combines with fixed mass of X in compounds B and C is $3:5$
$\begin{array}{ccc}\text{B}& 84/32& 3\\ \text{C}& m/16& 5\end{array}$
$\Rightarrow \frac{84/32}{m/16}=\frac{3}{5}$
$m=\frac{42\times 5}{3}=70$