Aluminium trifluoride is insoluble in anhydrous HF but dissolves on addition of NaF. Aluminium trifluoride precipitates out of the resulting solution when gaseous `BF_3` is bubbled through. Give reasons.

Assertion : When HCl gas is passed through a saturated aq. solution of NaCl, some NaCl precipitates out Reason : K_(sp) of NaCl decreases due to common ion effect

A scientist dissolved sodium metal in liquid NH_3 . He got a coloured solution. When the solution was kept for sometime then observed a gas buddling out. Give the colour of the solution and identify the gas evolved. Discuss the chemistry involved.

4.008 g of pure KCIO_(3) , was quantitatively decomposed to give 2.438 g of KCl and oxygen. KCl was dissolved in water and treated with AgNO, solution. The result was a precipitate of AgCl weighing 4.687 g. Under further treatment, AgCl was found to contain 3.531 g of Ag. What are the atomic weights of Ag, Cl and K relative to O = 16?