chapter 12 - QA ( anion+gas test )

Question 1

What are the steps, observations and inferences to carbonate ion test

Answer 1

• add dilute acid to solution
• pass the gas into limewater
• effervescence. Gas forms white ppt when bubbled into limewater.
• carbon dioxide gas is given off

Question 2

What is the steps, observations and inferences of chloride ion test

Answer 2

• add dilute nitric acid, then add silver nitrate solution
• white ppt is observed
• chloride ion is present. White ppt is silver chloride

Question 3

What is the steps, observations and inferences of iodide ion test

Answer 3

• add dilute nitric acid
• then add lead/silver nitrate solution
• yellow ppt is observed
• iodide ion is present. Yellow ppt is silver/lead iodide

Question 4

What are the steps, observations and inferences for nitrate ion

Answer 4

• add dilute sodium hydroxide
• then add a piece of aluminium foil
• warm mixture and test the gas given off with a piece of moist red litmus paper
• pungent gas produced which turns moist red litmus paper blue
• ammonia gas is produced. Nitrate ion is present

Question 5

What are the steps, observations and inferences to surfate ion test

Answer 5

• add dilute nitric acid then add barium nitrate solution
• white ppt is observed
• sulfate ion is present. White ppt formed is barium sulfate

Question 6

What are the tests and observations of hydrogen test

Answer 6

• place a lighted splint at the mouth of the test tube

- effervescence. Colourless and odourless gas extinguished lighted splint with a “pop” sound.

Question 7

What are the steps and observations of oxygen test

Answer 7

• insert a glowing splint into the test tube

- colourless and odourless gas rekindles /relights the glowing splint

Question 8

What are the steps and observations of carbon dioxide test

Answer 8

• add dilute acid to solution
• bubble the gas through limewater

-effervescence. Gas formed white ppt when bubbled through the limewater

Question 9

What are the steps and observations for chlorine gas test

Answer 9

• place apiece of damp litmus paper at the mouth of the test tube
• choking, yellow green gas is produced. The damp blue litmus paper turned red and then bleached by the gas

Question 10

What are the steps and observations for sulfur dioxide

Answer 10

• place a piece of filter paper soaked with acidified potassium manganate (VII) at the mouth of the test tube
• colourless and strong smelling gas turned potassium manganate (VII) colourless

Question 11

What are the steps and observations for ammonia gas

Answer 11

• gently warm the mixture and place a piece of damp red litmus paper at the mouth of the test tube
• colourless and pungent gas turned damp red litmus paper blue.