Questions carrying 2 marks : Addition of NaOH solution to a solution of `Zn Cl_2` produces a white precipitate which dissolves in excess of NaOH and forms soluble sodium zincate. Why?

Gradual addition of KI solution to Bi(NO_(3))_(3) solution initially produces a dark brown precipitate which dissolves in excess of KI to give a clear yellow solution. Write the chemical equations for the above reactions.

Questions carrying two marks : Why is KO^2 paramagnetic?

Addition of sodium thiosulphate solution to a solution of silver nitrate given 'X' as white precipitate, insoluble in water but soluble in excess thiosullphate solution to give 'Y'. On boiling in water, 'Y' gives 'Z'. 'X', 'Y' and 'Z' respectively are -

Addition of sodium thiosulphate solution to a solution of silver nitrate gives 'X' as white precipitate, insoluble in water but soluble in excess thiosulphate solution to give 'Y'. On boiling in water, 'Y' gives 'Z'. 'X', 'Y' and 'Z' respectively, are

The sodium salt of an unknown anion when heated with MgCl_2 forms a white precipitate. The anion is -

C Cl_4 does not give white precipitate while NaCI solution does with AgNO_3 solution— Explain why.

NaOH solution is added to Al_2(SO_4)_3) solution?

F_(2) gas is passed through 2% NaOH solution.

Name a bivalent element whose oxide is soluble in excess NaOH solution.