3C - Halide tests

    1)           State and explain the reactivity of the halogens as you go down Group 7:  [4]

                            More reactive down the group [1]   Due smaller atom  [1] 

                            Less shielding [1]  Greater attraction to capture an electron  [1]

 

    2)          This question is about the tests of the potassium halides.

                    a)  Complete the table below putting in the colours of the halides when silver nitrate is added [6]

                   

Halogen

Colour with AgNO3

Addition of dil / conc ammonia

Chlorine

White precipitate

Precipitate dissolves in dil

Bromine

Cream precipitate

Precipitate dissolves in conc

Iodine

Yellow precipitate

Precipitate does not dissolve

 

                    b)  Write equations for the 3 precipitate reactions   [3]

                            Balanced equation [1]  state symbols  [1]    x 3

                            KCl(aq)    +    AgNO3(aq)   à     AgCl(s)      +    KNO3(aq)

                            KBr(aq)    +    AgNO3(aq)   à     AgBr(s)      +    KNO3(aq)

                            KI(aq)    +    AgNO3(aq)   à     AgI(s)      +    KNO3(aq)