Suppose the elements X and Y combine toform two compounds XY2 and XsY2. When0.1 mole of XY2 weighs 10 g and 0.05 mole ofX3Y weighs 9 g, the atomic weights of X and312Y are(a) 40, 30(c) 20, 30(b) 60, 40(d) 30, 20

Suppose the elements X and Y combine toform two compounds XY2 and XsY2

1.	Suppose the elements X and Y combine toform two compounds XY2 and XsY2. When0.1 mole of XY2 weighs 10 g and 0.05 mole ofX3Y weighs 9 g, the atomic weights of X and312Y are(a) 40, 30(c) 20, 30(b) 60, 40(d) 30, 20
Answer» <p>let the molar mass of X be A and Y be B </p><p>now molar mass XY2 = A + 2B 10/(A+2B) = 0.1 => A +2B = 100.....(1)</p><p>and, molar mass X3Y2 = 3A+2B </p><p>=> 9/(3A+2B) = 0.05=> 3A +2B = 180....(2)</p><p>subtracting 1 from 2.=> 3A -A = 180-100 = 80=> A = 80/2 = 40.</p><p>so, B = 30.</p><p>option A.</p>