Cation 5 Flashcards
Group V Cations is sometimes called the
soluble group
True of False: Group 5 Cations don’t have a precipitate
True
GROUP V CATIONS:
• Sodium (Na+) lon
• Potassium (K+) lon
• Ammonium NH4+ lon
The salts of these cations, with few exceptions, are quite
soluble
This accounts for the fact that there is no __________ agent for this group.
precipitating
If a strong base such as _____________or _____________ is added to a solution containing ammonium ions and the solution is warmed, the escape of ammonia gas results.
KOH (Potassium hydroxide)
NaOH (Sodium hydroxide)
Mag escape and ammonia gas if may ara sang
Strong bases
The ammonia gas which escapes may be recognized by its ____ or by its action upon moist ________
odor
red litmus paper
The most liable qualitative tests for sodium and potassium ions in low concentrations are their identifying
flame spectra
confirms the presence of SODIUM IONS
INTENSE YELLOW FLAME persisting for several seconds
presence of POTASSIUM IONS
PALE VIOLET FLAME
TEST FOR SODIUM AND POTASSIUM IONS
Transfer one-half of the unknown sample to an evaporating dish and add
1 drop of concentrated HCI (Hydrochloric acid)
What is used to clean the wire
Diluted HCL
confirms the presence of SODIUM ION.
INTENSE YELLOW flame persisting for 5 seconds
in the absence of sodium ions, presence of potassium ions imparts a ________ color to flame when viewed with the naked eye.
pale violet
If yellow flame of sodium is present it will be necessary to view flame through a filter of _______.
cobalt glass
confirms the presence of POTASSIUM ION.
REDDISH-VIOLET flame persisting for about 2 seconds
In the test for Ammonium ion, Make solution alkaline with
3M KOH
(Potassium hydroxide)
confirms the presence of AMMONIUM ION.
Even shading of litmus paper from red to blue
Confirmation for Potassium ion:
FLAME TEST: (in Cobalt glass)
Lilac
Confirmation for Potassium ion:
FLAME TEST: (w/o cobalt glass)
Pink
Confirmation for Ammonium ion
Reagent used:
strong base (either NaOH or KOH)
Used to upset the equilibrium forming ammonia gas
Strong bases such as NaOH or KOH
