Organics Tests

Question 1

How do we test for carboxylic acids?

Answer 1

• add H2O and universal indicator
• solution turns orange/red indicating pH 3 (weak acid)
  OR
• add NaHCO3
• fizzing and CO2 given off (can be bubbled through limewater)

Question 2

How do we test for aldehydes?

Answer 2

• warm with Fehling’s solution, goes blue solution to brick red precipitate
• warm with Tollen’s, goes from colorless to silver mirror forming
• turns acidified potassium dichromate VI green (so do primary and secondary alcohols!!)

Question 3

How do we test for alkenes?

Answer 3

• add bromine water

- solution goes orange to colourless

Question 4

How do we test for primary, secondary and tertiary alcohols?

Answer 4

• add acidified potassium dichromate VI
• orange colour turns green for primary and secondary
• no change for tertiary

Question 5

How do we test for haloalkanes?

Answer 5

• add NaOH and warm
• acidify with HNO3
• add AgNO3 and precipitate of AgX should form