Qualitative Analysis

Name the gas that is being tested. What is the observation for the test?

• oxygen, splint rekindles

• Hydrogen, squeaky pop

• Carbon dioxide, the flame extinguishes

• water, vapor forms at the mouth of test-tube

When a glowing splint is placed into the flask the flames rekindle. What gas is present?

• ammonia

• sulphur dioxide

• carbon dioxide

• oxygen

When this gas is bubbled through potassium manganate (VII) the solution changes from purple to colorless. Which was was present?

• chlorine

• ammonia

• nitrogen dioxide

• sulphur dioxide

When this gas is tested it changes damp blue litmus paper to red and then bleaches it. Which gas is being tested for?

• sulphur dioxide

• ammonia

• chlorine

• water

Cobalt (II) Chloride paper was held at the mouth of the test tube and the color changed from blue to pink. What was the gas that was present?

• ammonia

• oxygen

• water vapour

• chlorine

A few drops of sodium hydroxide solution were added to an unknown ionic compound Z and no precipitate was seen. On warming, a pungent gas was evolved. The gas would MOST likely

I turn red litmus paper blue

II form dense white fumes with hydrogen chloride

III turn acidified potassium dichromate (VI) solution from orange to green.

• I only

• III only

• I and II only

• I, II and III

Aqueous ammonia is added, until in excess, to a solution containing Cu2+ ions. Which of the following observations would be made?

• a blue precipitate forms, which remains in excess.

• A blue precipitate forms, which dissolves in excess forming a deep blue solution.

• A blue precipitate forms, which remains in excess and turns deep blue on standing.

• No precipitate forms and the solution remains pale blue.

A few drops of silver nitrate solution were added to sodium chloride solution, followed by aqueous ammonia. Which of the following observations were made?

• A pale cream precipitate formed, which partially dissolved in aqueous ammonia

• A pale cream precipitate formed, which remained undissolved in aqueous ammonia.

• A white precipitate formed, which partially dissolved in aqueous ammonia.

• A white precipitate formed, which dissolved in aqueous ammonia.