The molecular masses of sulphate and hydroxide of a metal M are 142 and 40 respectively. Calculate atomic mass and valency of the metal.

The molecular masses of sulphate and hydroxide of a metal M are 142 an

1.	The molecular masses of sulphate and hydroxide of a metal M are 142 and 40 respectively. Calculate atomic mass and valency of the metal.
Answer» Solution :Let the valency of METAL be x and atomic meight be m. `:." Metal sulphate is "M^(+x)SO_4^(-2)rArrM_2(SO_4)_x` `:. " Metal HYDROXIDE is "M^(+x)OH_4^(-2)rArrM(OH)_x` `:." Molecular weight of metal sulphate is "` `2m+96x=142to(1)` Molecular weight of metal hudroxide is `m+17x=40` `rArr2m+34x=80to(2)` From (1) and (2) `rArr2m+34x=80` `((-)(-)(-))/(62x=62)` `rArrx=1` `:." From" (1)rArr2m+96(1)=142` `rArr2m=142-96=46rArrm=23` `:. " Valency and atomic weight of the metal are 1 and 23 RESPECTIVELY"`.