3 elements x , Y and Z form a Dobereiner triad . Their atomic weights are in the ratio 5 : 11 : 17 . If the sum of the atomic weights of extreme elements is 176 , then find the atomic weights of X , Y and z .

Options

A. `{:(X,Y,Z),(40,80,176):}`
B. `{:(X,Y,Z),(40,88,136):}`
C. `{:(X,Y,Z),(40,80,120):}`
D. `{:(X,Y,Z),(80,100,120):}`

Answer

B

Explanation

Let the given ratio of atomic weights X , Y , Z be 5X , 11X , 17X respectively .
Sum of extreme elements
(5X + 17X) = 176
Given
`22X = 176 , X = (176)/(22) = 8 `
`:.` At weight of `X = 5 xx 8 = 40 ` ,
`Y = 11 xx 8 = 88` ,
`Z = 17 xx 8 = 136` .