Carbonates, Halides & Sulfates

Test yourself

Reactions of Carbonates

When carbonates react with dilute acids, the following products are formed:

A salt

Carbon dioxide

Water

Testing for Halides

Halide ions are negatively charged (they are anions). There are 2 steps to halide testing:

Add dilute nitric acid

Add dilute nitric acid to an unknown solution.
- This removes carbonate ions. These could disrupt test results by forming a precipitate with the silver ions added in step 2.

Add silver nitrate

Add silver nitrate to the same solution.
- If halide ions are present, they will form a precipitate with the silver ions:
  - Ag⁺(aq) + Cl^-(aq) → AgCl(s) (silver chloride is white).
  - Ag⁺(aq) + Br^-(aq) → AgBr(s) (silver bromide is cream).
  - Ag⁺(aq) + I^-(aq) → AgI(s) (silver iodide is pale yellow).

Testing for Sulfates

Sulfates are compounds that contain SO₄^2- ions. There are 2 steps to sulfate testing:

Add dilute hydrochloric acid

Add dilute hydrochloric acid to an unknown solution.
- This removes carbonate ions. These could disrupt test results by forming a precipitate with the barium ions added in step 2.

Add barium chloride

Add barium chloride to the same solution.
- If sulfates are present, the white precipitate barium sulfate will form:
  - Ba²⁺(aq) + SO₄^2-(aq) → BaSO₄(s)

1Biology

1.1Practicals

1.1.1Microscope & Bacteria

1.1.2Bacteria

1.1.3Osmosis Tests

1.1.4Osmosis & Food Tests

1.1.5Enzymes

1.1.6Enzymes 2

1.1.7Photosynthesis & Plant Responses

1.1.8Photosynthesis Experiments

1.1.9Reaction Time

1.1.10Quadrats

1.1.11Decay

2Chemistry

2.1Practicals

2.1.1Salts

2.1.2Neutralisation

2.1.3Titration

2.1.4Electrolysis

2.1.5Electrolysis 2

2.1.6Rate of Reaction

2.1.7Rate of Reaction 2

2.1.8Chromatography

2.1.9Identifying Gases

2.1.10Identifying Gases 2

2.1.11Identifying Ions

2.1.12Carbonates, Halides & Sulfates

2.1.13Flame Emission Spectroscopy

2.1.14Water Purification

2.1.15Water Purification 2

3Physics

3.1Practicals

3.1.1Specific Heat Capacity

3.1.2Thermal Capacity & Insulation

3.1.3Latent Heat

3.1.4Resistance & Current

3.1.5Resistance & Current 2

3.1.6Density

3.1.7Density 2

3.1.8Force & Extension - Springs

3.1.9Waves - Ripple Tank

3.1.10Light

3.1.11Light Reflection & Refraction

3.1.12Radiation

3.1.13Radiation 2

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