Kevin Nash
Last Activity: 10 Years ago
As the solid B forms a hydrated salt C with Al
base 2(SO base 4) base 3; B should be sulphate of a monovalent cation, i.e. M base 2SO base 4. Now since
sulphate of a monovalent cation contains one sulphur atom per mol, weight of
metal sulphate obtained by 32.1 g (at. Wt. of S) should be the molecular weight
of the metal sulphate. Thus, - 0.321 g of sulphur is present in 1.743 g of B
?
32.1 g of sulphur is present in = 1.743/0.321 *32.1 = 174.3 g
Thus mol. wt. of B (M base 2SO base 4) = 174.3
g mol^-1
2x + 32.1 +64 = 174.3 (at wt. of M = x]
2x = 78.2 ? x = 39.1
Atomic weight 39.1 corresponds to metal
potassium, K. Thus B is K base 2SO base 4, and C is K base 2SO base 4. Al base
2(SO base 4) base 3 24H base 2O
Nature of
compound A : since A is a binary compound of potassium and
it reacts with sulphur to form K base 2SO base 4, it must be oxide of
potassium, probably potassium superoxide (KO base 2) which is supported by the
given data.
2KO base 2 +S ? K base 2SO base 4
(A) (B)
2(39.1 +32) = 142.2
32.1 g of S reacts with 142.2 g of KO base 2
0.321 g of S reacts with = 142.2/32.1 * 0.321
= 1.422 g
Similarly,
32.1 g of S gives 1174.3 g of K base 2SO base
4
0.321 g of S gives = 174.3/32.1 *0.321 = 1.743
g
Both these datas are also given in the problem.
Thus A is KO base 2.
