Question

Number of gm of oxygen in 32.2 g $Na_{2}SO_{4}.10H_{2}O$is

• A. 20.8
• B. 22.4
• C. 2.24
• D. 2.08

Answer 1

Answer: (B)

22.4

Answer 2

$Na_{2}SO_{4}\mspace{6mu}.\mspace{6mu} 10H_{2}O$ $= 2 \times 23 + 32 + 4 \times 16 + 10 \times 18$

$= 46 + 32 + 64 + 180 = 322gm$

322gm $Na_{2}SO_{4}.10H_{2}O$ contains = 224 gm oxygen

32.2gm $Na_{2}SO_{4}.10H_{2}O$ contains

= $\frac{32.2 \times 224}{322} = 22.4gm$