Lesson: Identifying Salts

Q1:

A white salt is soluble in water and reacts with hydrochloric acid to produce a colorless gas. When barium chloride is added to a solution of the salt in water, a white solid precipitates. In a flame test, the salt produces a red flame.

Q2:

A white salt is soluble in water and produces a red color in a flame test. Addition of silver nitrate to an aqueous solution of the salt results in a yellow precipitate that does not dissolve in concentrated aqueous ammonia. Addition of sodium hydroxide to a solution of the salt has no visible effect, but adding sodium carbonate produces a white precipitate.

Q4:

A collection of white salts have been placed separately into unlabeled bottles. It is known that each salt contains ions of cesium, magnesium, or barium combined with nitrate, chloride, sulfate, or carbonate anions. A student identifies each salt by adding five reagents consecutively to a single sample of the material in a test tube, without filtering between tests. After every test, the student records their visual observations as shown in the table.

	1. Water	2. Nitric Acid	3. Sodium Hydroxide	4. Nitric Acid	5. Silver Nitrate
Cesium Nitrate	Colorless solution	Colorless solution	Colorless solution	Colorless solution	Colorless solution
Compound	White solid	Gas bubbles and colorless solution	Colorless solution	Colorless solution	Colorless solution
Compound	Colorless solution	Colorless solution	White solid	Colorless solution	White solid
Compound	White solid	White solid	White solid	White solid	White solid

Q5:

A student adds magnesium nitrate and barium nitrate to three cesium salts A–C in an aqueous solution. The student records the visual observations from these tests in a table, as shown.

Salt	Magnesium Nitrate	Barium Nitrate
A	White precipitate	White precipitate
B	Colorless solution	White precipitate
C	White precipitate	Colorless solution

Q6:

When a solid material is added to a dilute aqueous solution , an exothermic reaction takes place and a gas is produced. A number of possible observations are shown in the table.

Observation	Precipitate	Gas Test with a Lit Splint	Gas Test with Limewater
1	White	Popping sound	No change
2	None	Extinguishes flame	Cloudy solution
3	None	Intensifies flame	No change
4	White	Extinguishes flame	Cloudy solution
5	None	Popping sound	No change

Q7:

Different nitrate salts are added separately to dilute aqueous solutions of five sodium salts. The results of these tests are shown in the table.

Sodium Salt
1	White solid	White solid	Solution	Solution
2	White solid	White solid	White solid	White solid
3	Yellow solid	Yellow solid	Solution	Solution
4	Solution	White solid	Solution	White solid
5	Brown solid	White solid	White solid	Solution

Q9:

A salt produces a green color in a flame test. In aqueous solution, the salt reacts with a number of other compounds, as shown.

Q11:

A metallic element reacts to form soluble salts when added to hydrochloric, nitric, or sulfuric acids. When sodium hydroxide is added to solutions of these salts, a white solid precipitates.