Question

100 g sample of clay (containing 19% $H_{2}O,$ 40% silica, and inert impurities as rest) is partially dried so as to contain 10% of $H_{2}O$.
Which of the following is/are correct statement(s)?

• A. The percentage of silica in partially dried clay is 44.4%
• B. The mass of partially dried clay is 90 g
• C. The percentage of inert impurity in partially dried clay is 45.6%
• D. The mass of water evaporated is 10 g

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A The percentage of silica in partially dried clay is 44.4%
B The mass of partially dried clay is 90 g
C The percentage of inert impurity in partially dried clay is 45.6%
D The mass of water evaporated is 10 g

Given, 100 g of the sample,
mass of silica = 40 g
mass of water = 19 g
mass of impurities = 100 -59 = 41 g

After drying, the percentage of water is 10 %. Let a g is the mass of water lost.
$\Rightarrow \frac{19-a}{100-a}\times 100=10$
$a=10$ g
Mass of the clay after drying = 100 - 10 = 90 g
percentage of silica = $\frac{40}{90}\times 100=44.4$
percentage of impurities = $\frac{41}{90}\times 100=45.6$