### Chemistry Practical

goals
The aqueous solution of inorganic compound $(X)$ yielded a white precipitate when treated with dilute $HNO_3$ and $AgNO_3$. Another sample of the solution of $(X)$ when treated with $NaOH$ gave a white precipitate first which dissolved in excess of $NaOH$ yielding a colorless solution. When $H_2S$ gas was passed through that solution a white precipitate was obtained.
Identify the compound $(X)$ and give the reactions.
Identify the inorganic salt $A$ whose aqueous solution gives following reactions.
(i) pale yellow precipitate with $AgNO_3$ solution, insoluble in dil $HNO_3$
(ii) white precipitate with $NH_4OH$ and also with $NaOH$ solution. However the precipitate does not dissolve in excess of $NH_4OH$ but soluble in excess of $NaOH$.
Identify $(A),\:(B),\:(C)$ & $(D)$ and give their chemical formulae:
(i) $(A)+NaOH\overset{Heat}{\longrightarrow} NaCl+NH_3+H_2O$
(ii) $NH_3+CO_2+H_2O\longrightarrow (B)$
(iii) $(B)+NaCl\longrightarrow (C)+NH_4Cl$
(iv) $(C)\overset{Heat}{\longrightarrow} Na_2CO_3+H_2O+(D)$
An inorganic lewis acid $[X]$ gives gelatinous white ppt. with $NH_4OH$ in presence of $NH_4Cl$. $[X]$ will respond to which of the following characteristics :
A test tube containing a nitrate and another containing a bromide and $MnO_2$ are treated with conc. $H_2SO_4$. The brown fumes evolved are passed in water. The water will be coloured by the :