A qualitative analysis puzzle - Journal of Chemical Education (ACS

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VOL.3, No. 9

A QUALITATIVE ANALYSISFUZZLE

1071

A QUALITATIVE ANALYSIS PUZZLE CARLOTTO, UNIVERSITYOR MAINE,ORONO, MAINE

The puzzle given here is somewhat different from all standard types of puzzles. A good knowledge of the properties of the ions is required to solve it if no references to text-books are made. The idea is to identify ten unknown solutions by studying their reactions with each other. Thus a certain group of ten solutions of single simple inorganic compounds (A, B, C, -, -, -, -, -, -, J) was taken and mixed together in all possible combinations of pairs. The observations, as given in the following table a t the junction of lines drawn from the letters representing the said solutions in the top and left margins, were noted. Thus, solution A added to solution B gave a yellow precipitate, soluble in HNOJ; solution A added to solution C gave a white precipitate, soluble in HNOI, etc. Following the table are a few other observations which were nnted. The problem is to identify the ten solutions from the data given. A Yellow PPf. sol.

in HNOI White ppt 101. in HNOa

Red ppt. sol. in acids and NHaOH

White ppt. 301. in HNOI

mite p p t sol. in acids

mite ppt. sol. in NHlOH

vellow ppt. sol.

Yellow ppt. sol. in HCI and HNOI

White White ppt. in- ppt. red sol. in solution acids ppt. sol. sol. in in acids NHdOH

kmonyellow PPt. sol. in acids

yellow ppt. in-I. in acids sol. in

in HNOI

Yellow ppt. 301. in HNOI

Na,s,Oa White p p t sol. in HNOI

White ppt. sol. in acids

mite NO ppr ppt. Soh. gives purple color with CCI,

Red ppt. Brown

801.in ppt. sol. acids sol. in HCI in NHaOH

Black ppt. sol. in HNOI

No ppt. If HCI is added white PPt.

Rlaek

Dark

ppt. in- green sol. in ppt. sol. acids ex- in acids cept C0"C

HPO* or HNOa

white mite p p t 501. ppt. sol. in acid. in HNOI and a1kalis

No ppt.

White ppt. sol. in acids gar evol, turns PbAn black

Yellow

ppt. $01. in nlkali sulfidep

A

I

B

White p p t sol. in HNOS

White ppt. sol. in acids

White ppt. inrol. in acids except

No ppt. orange solution

C white ppt. sol, in N&OH

D E F G Redwhite white No ppt. brown ppt. sol. ppt. sol. slight ppt. sol. in acids in acids cfferves. in acids with cene evol. of

Slight ppt. sol. in N-OH Glans etched by fumes

2 gases white evolved ppt. on htg. insol. limewater in acids milky except combus- eonc. tible HBOa

R

I

No ppt.

co, J ,

cone.

H&OI

ADDITZONAL

No ppt.

No reaction

DATA

All solutions are colodes eexcept solutionn B and D which are light yellow. Solutions G. H. and J are aeido. Solution A gives the b r o w ring test. Soltltion E gives a green flame test and solution I a yellow flame test.

(Answers to be published i n the next issue.)

White Evol. of pP. CO, Colloidal Odor SO.