Chemistry: Cation Identification and Flame Tests

Fill-in-the-blank practice flashcards reviewing cation flame tests and precipitate identification using sodium hydroxide.

In a flame test, the metal ion lithium ($Li^+$) produces a __________ flame.

Red

In a flame test, the metal ion sodium ($Na^+$) produces a __________ flame.

Yellow

In a flame test, the metal ion potassium ($K^+$) produces a __________ flame.

Lilac

In a flame test, the metal ion calcium ($Ca^{2+}$) produces an __________ flame.

Orange

In a flame test, the metal ion copper ($Cu^{2+}$) produces a __________ flame.

Green

To prepare a wire for a flame test, clean it by dipping in __________ and heating it in a Bunsen flame.

$$HCl$$

A flame test is only suitable for testing a sample that contains a __________.

single metal ion

Adding sodium hydroxide to a metal compound solution allows us to identify the __________.

cation

A precipitate forms when sodium hydroxide reacts with metal compound solutions because metal hydroxides are __________.

insoluble

To test for cations using precipitation, dissolve the sample in water and add __________ a few drops at a time.

$$NaOH$$

The copper ion ($Cu^{2+}$) forms a precipitate of $Cu(OH)_2$ with a __________ colour.

Blue

The iron(II) ion ($Fe^{2+}$) forms a precipitate of $Fe(OH)_2$ with a __________ colour.

Green

The iron(III) ion ($Fe^{3+}$) forms a precipitate of $Fe(OH)_3$ with a __________ colour.

Brown

When aluminium ions ($Al^{3+}$) react with sodium hydroxide, they produce a white precipitate with the chemical formula __________.

$$Al(OH)_3$$

When calcium ions ($Ca^{2+}$) react with sodium hydroxide, they form a white precipitate with the formula __________.

$$Ca(OH)_2$$

When magnesium ions ($Mg^{2+}$) react with sodium hydroxide, they form a white precipitate with the formula __________.

$$Mg(OH)_2$$

Unlike other white hydroxide precipitates, adding excess $NaOH$ causes __________ to dissolve.

$$Al(OH)_3$$