A solution contains some or all of the ions Cu2+, Al3+, K+, Ca2+, Ba2+, Pb2+, and NH4+. The following tests were performed, in order, on the solution.

Addition of 6 M HCl produced no reaction.

Addition of H2S with 0.2 M HCl produced a black solid.

Addition of (NH4)2S produced a white solid.

Addition of (NH4)2HPO4 in NH3 produced no reaction.

The final supernatant when heated produced a purple flame.

Identify which of these ions were present in the solution, which were absent, and for which ones no conclusions can be drawn.

Drag the appropriate items to their respective bins.

bins are: present. absent. and Inclusive.

options: K+ Ba2+ NH4+ Al3+ Pb2+ Ca2+ Cu2+

Part B

Select the reagent that will separate the pairs of ions listed.

yea hi

explanation:

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol