Cation Group Identification and Confirmation

Vocabulary flashcards for cation analysis experiments.

Ammonium Cation (NH₄⁺)

Cation in Group zero, identified by adding Na₂CO₃ solution to the salt solution and observing no precipitate.

Lead Cation (Pb²⁺)

Cation in Group I, identified by adding dilute HCl to the salt solution and observing a white precipitate.

Copper Cation (Cu²⁺)

Cation in Group II, identified by mixing the salt solution with dilute HCl and passing H₂S, resulting in a black precipitate.

Aluminum Cation (Al³⁺)

Cation in Group III, identified by mixing the salt solution with excess NH₄Cl, shaking well, and adding excess NH₄OH, forming a white gelatinous precipitate.

Zinc Cation (Zn²⁺)

Cation in Group IV, identified by mixing a little of the salt solution with NH₄Cl & NH₄OH and passing H₂S, resulting in a white precipitate.

Barium or Calcium Cations (Ba²⁺ or Ca²⁺)

Cations in Group V, identified by mixing a little of the salt solution with NH₄Cl, NH₄OH, and (NH₄)₂CO₃ solutions, resulting in a white precipitate.

Magnesium Cation (Mg²⁺)

Cation in Group VI, identified by mixing a little of the salt solution with NH₄Cl, NH₄OH, and Na₂HPO₄ solutions, scratching the inner sides of the test tube with a glass rod, resulting in a white precipitate.

Nessler's Reagent Test

A confirmatory test for ammonium ions (NH₄⁺), resulting in a brown precipitate when added to a solution containing ammonium.

Potassium Chromate (K₂CrO₄) Test for Lead

A test to identify lead. The salt solution is mixed with acetic acid and K₂CrO₄ solution, resulting in a yellow precipitate.

Potassium Iodide (KI) Test for Lead

A confirmatory test for lead. A golden yellow precipitate is formed, which dissolves in boiling water and appears as golden spangles on cooling.

NaOH Test for Aluminum

A test to identify aluminum ions (Al³⁺). Adding NaOH solution drop by drop till in excess, will result in a white precipitate that dissolves in excess sodium hydroxide.

Cobalt Nitrate Test

A confirmatory test for aluminum ions (Al³⁺). When a filter paper strip soaked in the solution is dried and burnt to ashes with cobalt nitrate a blue tinted ash is formed.

NaOH Test for Zinc

A test to identify Zinc ions (Zn²⁺). Adding NaOH solution drop by drop till in excess, will result in a white precipitate is formed which is soluble in excess of NaOH giving a clear solution

Flame Test for Barium

A confirmatory test for barium ions (Ba²⁺). The salt is made into a paste with conc.HCl, Pale green color is imparted to the flame.

Ammonium Oxalate Test for Calcium

A test to identify calcium ions (Ca²⁺). Mixing the salt solution with ammonium chloride, ammonium hydroxide, and ammonium oxalate solutions and a white precipitate appears.

Flame Test for Calcium

A confirmatory test for calcium ions (Ca²⁺). The salt is made into a paste with conc.HCl, Brick red color is imparted to the flame.

Magneson Reagent Test for Magnesium

A test to identify magnesium ions. Adding two drops of magneson reagent and NaOH to a little of the salt solution results in a blue precipitate.

Cobalt Nitrate Test for Magnesium

A confirmatory test for magnesium ions (Mg²⁺). When a filter paper strip soaked in cobalt nitrate solution is burnt to ashes, a pink ash is obtained.

Ammonium Cation (NH₄⁺)

Identified by adding Na₂CO₃; no precipitate forms.

Lead Cation (Pb²⁺)

Group I; white precipitate forms with dilute HCl.

Copper Cation (Cu²⁺)

Group II; black precipitate forms with H₂S and dilute HCl.

Aluminum Cation (Al³⁺)

Group III; white gelatinous precipitate forms with excess NH₄Cl and NH₄OH.

Zinc Cation (Zn²⁺)

Group IV; white precipitate forms with NH₄Cl, NH₄OH, and H₂S.

Barium/Calcium Cations (Ba²⁺ or Ca²⁺)

Group V; white precipitate forms with NH₄Cl, NH₄OH, and (NH₄)₂CO₃.

Magnesium Cation (Mg²⁺)

Group VI; white precipitate forms with NH₄Cl, NH₄OH, and Na₂HPO₄; scratch test tube.

Nessler's Reagent Test

Confirms NH₄⁺; brown precipitate forms.

Potassium Chromate (K₂CrO₄) Test for Lead

Identifies Lead; yellow precipitate forms with acetic acid and K₂CrO₄.

Potassium Iodide (KI) Test for Lead

Confirms Lead; golden yellow precipitate forms; dissolves in hot water, golden spangles on cooling.

NaOH Test for Aluminum

Identifies Aluminum; white precipitate dissolves in excess NaOH.

Cobalt Nitrate Test

Confirms Aluminum; blue tinted ash forms with cobalt nitrate.

NaOH Test for Zinc

Identifies Zinc; white precipitate dissolves in excess NaOH.

Confirms