Q29 / 90 · JEE Main 2022 (27 Jun Shift 1) · Chemistry

Two elements $A$ and $B$ which form $0.15$ moles of $A_{2} B$ and ${AB}_{3}$ type compounds. If both $A_{2} B$ and ${AB}_{3}$ weigh equally, then the atomic weight of $A$ is____times of atomic weight of $B$ .

Correct answer: 2

Solution

Given: Molar mass of $A_{2} B = {AB}_{3}$

$∴ (2 A + B) = (A + 3 B) [\begin{array}{l} A \to Atomicwt . of A \\ B \to Atomicwt . of B \end{array}]$

$\Rightarrow A = 2 B$

$∴$ atomic wt. of $A$ is 2 times of atomic wt. of $B$ Integer answer is $2$ .

Hence, the correct answer is 2.