1. Test on Ethyne

2. Give the general formula of alkynes. [1]
Name and give formula of the second member of the series. [2]
What is their functional group? [1]
What two substances would you react to make ethyne? [2]
Give equation for the reaction. [3]
Draw labelled diagram of apparatus used? [4]
What is the ethyne bubbled through and why? [5]
Describe what you would see as the reaction proceeds? [6]

3. Ethyne is an unsaturated hydrocarbon. What does this mean? [4]
Give two tests you could use to show this.[8]
What happens when you react ethyne with hydrogen? Give both scenarios.[4]
Complete the equation and name the product C2H2 + 2 Br2 = [3]
Give a major use of ethyne. Why is it used for this? [3]
Describe burning of ethyne in air plus equation. [4]
Smell of ethyne? [2]
Name a substance it is soluble in and why? [3]
Name a substance it is insoluble in and why? [3]
Give equation for reaction of ethyne with water. Name product. [3]

4. Give the general formula of alkynes. [1] CnH2n-2
Name and give formula of the second member of the series. [2] Propyne / C3H4
What is their functional group? [1] C  C
What two substances would you react to make ethyne? [2] calcium (di)carbide / water
Give equation for the reaction. [4] CaC H2O = C2H2 + Ca(OH)2
Draw labelled apparatus used? [4]
What is the ethyne bubbled through and why? [5] acidified / CuSO4 / remove impurities / H2S or PH3 / from CaS or Ca3P2
Describe what you would see as the reaction proceeds? [6] grey / lumpy / solid / becomes white / powder / increase in volume / heat produced

5. an unsaturated hydrocarbon. What does this mean
an unsaturated hydrocarbon. What does this mean? [4] contains double / or triple bond / contains only C / and H
Give two tests you could use to show this.[8] acidified / MnO4- / purple to / colourless / Mn2+ / or acidified / Cr2O72- / amber / to green / Cr3+ / or Br / water / red to /colourless
What happens when you react ethyne with hydrogen? Give both scenarios and the conditions that may be used.[6] ethene / or ethane formed / 1 H2 / or 2 H2 / catalyst / heat
Complete the equation and name the product C2H2 + 2 Br2 = [2] C2H2Br4 / 1,1,2,2 tetrabromoethane
Give a major use of ethyne. Why is it used for this [3] oxy-acetylene burner / burns with a very hot flame / in excess air.
Describe burning of ethyne in air. [6] yellow / smoky flame
Smell of ethyne? [2] sickly / sweet
Name a substance it is soluble in and why?[3] cyclohexane / both / non-polar
Name a substance it is insoluble in and why?[3] water / it non-polar / water polar
Give equation for reaction of ethyne with water. Name product. [4]
C2H2 + H2O = CH3CHO ethanal [63]