100 g sample of clay (containing 19% H₂O, 40% silica, and inert impurities as rest) is partially dried so as to contain 10% H₂O.

which of the following is/are correct statements(s)?

$\begin{array}{l} \\ \% \mathrm{in} \mathrm{original} \mathrm{clay}] \Rightarrow \\ \% \mathrm{after} \mathrm{partial} \mathrm{drying}]\Rightarrow \end{array} \begin{array}{c}\mathrm{Silica}\\ 40\\ \mathrm{a}\end{array} \begin{array}{c}{\mathrm{H}}_2\mathrm{O}\\ 19\\ 10\end{array} \begin{array}{c}\mathrm{Impurities}\\ 100 - (40 + 19)= 41\\ 100 - (\mathrm{a} + 10) = 90 - \mathrm{a}\end{array}$

On heating, only water evaporates from clay, whereas silica and impurities are left as it is. Therefore,% ratio of silica and impurities remains unchanged, i.e., 
$\frac{40}{\mathrm{a}}=\frac{41}{90-\mathrm{a}},\therefore \mathrm{a}=44.4\mathrm{\%}$

% of impurities after partial drying  = (90 - a)

                                                       = (90 - 44.4) 

                                                       = 45.6 %

Mass of H₂O evaporated= (19 -10) = 9 g