Question

11. What is the value of a?
†
as
66aº
27a9
56aº
31ay
(a) 90°
(c) 180°
High Order Thinkin
(b) 10°
(d) 2°​

Answer 1

Answer:

Element mass % Atomic mass(g) m%/At. mass Integral ratio

Na 14.31 23 0.622 2

S 9.97 32 0.311 1

H 6.22 1 6.22 20

O 69.5 16 4.34 14

Empirical formula is therefore Na

2

SH

20

O

14

empirical mass=2×23+32+20×1+14×16=322g

Given:

Molecular mass = 322 g

∴ molecular formula =empirical formula=Na

2

SH

20

O

14

Given that all the hydrogen in the compound is reset in combination with oxygen as water of crystallisation

If water of crystallization are nH

2

O then, 2n=20

or n=10

Crystallized water is 10H

2

O remaining atoms are Na

2

SO

4

therefore, the molecule is Na

2

SO

4

.10H

2

O