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chemistry practical identifying unknown comounds need help plz Watch

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    Hey I have my ch6 practical exam coming up and we have to identify 6 compounds and theirs 8 all together that they could be.
    what test can i use to show I have diphenylmethanone, benzonitrile and ethanamide?

    I've been trying to think what i could do now for past week and I just keep going round in circles. There is limited resources I can use too :
    dilute sodium hydoxide
    dilute sulfuric acid
    sodium hydrogencarbonate
    litmus paper
    sodium nitrite
    tollens and iodoform
    Any ideas would be greatly appreciated
    thankyou
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    (Original post by elliegurl297)
    Hey I have my ch6 practical exam coming up and we have to identify 6 compounds and theirs 8 all together that they could be.
    what test can i use to show I have diphenylmethanone, benzonitrile and ethanamide?

    I've been trying to think what i could do now for past week and I just keep going round in circles. There is limited resources I can use too :
    dilute sodium hydoxide
    dilute sulfuric acid
    sodium hydrogencarbonate
    litmus paper
    sodium nitrite
    tollens and iodoform
    Any ideas would be greatly appreciated
    thankyou
    Hmmm let's see, diphenylmethanone is a ketone but I think it was a methyl ketone so it shouldn't be oxidised by tollens reagent but it should give a yellow precipitate of CHI3 with the iodoform test.

    Benzonitrile.., I think you should try to hydrolyse by heating with dilute sulphuric acid to get benzoic acid which should fizz and give off CO2 gas due to the acidity of the COOH group with NaHCO3

    Ethanamide I believe is alkaline so would it just turn the litmus from red to blue ? I believe you could also use sodium nitrite if you reduce the benzonitrile to phenylamine and diozotise it using sodium nitrite I think that gave a yellow precipitate.

    That's all I can think of, off the top of my head. Hope it was useful.
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    (Original post by xSkyFire)
    Hmmm let's see, diphenylmethanone is a ketone but I think it was a methyl ketone so it shouldn't be oxidised by tollens reagent but it should give a yellow precipitate of CHI3 with the iodoform test.

    Benzonitrile.., I think you should try to hydrolyse by heating with dilute sulphuric acid to get benzoic acid which should fizz and give off CO2 gas due to the acidity of the COOH group with NaHCO3

    Ethanamide I believe is alkaline so would it just turn the litmus from red to blue ? I believe you could also use sodium nitrite if you reduce the benzonitrile to phenylamine and diozotise it using sodium nitrite I think that gave a yellow precipitate.

    That's all I can think of, off the top of my head. Hope it was useful.
    you sure can think off the top of your head.

    are the compounds to be identified told before the practical exams? i do the ATP papers
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    (Original post by obviouslystudying)
    you sure can think off the top of your head.

    are the compounds to be identified told before the practical exams? i do the ATP papers
    haha dw, it's only because I had my chemistry synoptic exam 3 days ago that I remember this stuff so well :p:

    Also for my practical they gave a bit of background and you did a series of tests and noted down the observations and inferences. Then you put down what you think it was. Like I did a really basic one with aldehydes and ketones using tollens reagent and iodoform and it originally said it was a 4 carbon compound so my answers were something like butanal and butanone/butan-2-one.. I think either was acceptable lol
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    (Original post by xSkyFire)
    Hmmm let's see, diphenylmethanone is a ketone but I think it was a methyl ketone so it shouldn't be oxidised by tollens reagent but it should give a yellow precipitate of CHI3 with the iodoform test.

    Benzonitrile.., I think you should try to hydrolyse by heating with dilute sulphuric acid to get benzoic acid which should fizz and give off CO2 gas due to the acidity of the COOH group with NaHCO3

    Ethanamide I believe is alkaline so would it just turn the litmus from red to blue ? I believe you could also use sodium nitrite if you reduce the benzonitrile to phenylamine and diozotise it using sodium nitrite I think that gave a yellow precipitate.

    That's all I can think of, off the top of my head. Hope it was useful.
    diphenylmethanone is not a methyl ketone and will not give the iodoform reaction.

    If you hydrolyse benzonitrile to benzoic acid you will have to purify it thoroughly to remove all traces of sulphuric acid before testing with sodium hydrogen carbonate. Probably easier just to cool down the aqueous solution and watch the benzoic acid precipitate out - add sodium hydroxide and watch it redissolve. Add acid and watch it precipitate out... Repeat until you get bored.

    The ethanamide will give ammonia on heating with sodium hydroxide solution (test with damp indicator paper -> blue)
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    hey thankyou everyone for your comments. If i test ethanamide without heating it with sodium hydroxide will it still turn the indicator paper blue?
    and also i forgot to say how can you test for a ethylbenzcarboxylate (ester)
 
 
 
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