sodium hydrogensulfate

Discussion in 'Supporting Chemistry' started by Franklin, Nov 7, 2019.

  1. Hi all,

    I am currently setting up the first a level chemistry required practical. "Make up a volumetric solution and carry out a simple acid-base titration"

    We ordered in sodium hydrogensulfate, but it's in huge lumps that I can't break up. The students need to make up their own solutions but can't possibly with this.

    Am I missing something?

    Did I order the wrong thing?

    Help please!!
     
    Last edited: Nov 7, 2019
  2. 007

    007 COMMITTEE

    It's moderately soluble in water as far as I'm aware about 30g per 100 ml of water. As I don't know which practical you are setting up, I've always used sodium carbonate to make a solution and then titrated this against HCl using methyl orange as an indicator. (we don't use the really cheap sodium carbonate powder used for chemical disposal, as this produces cloudy solutions, I use specially bought for this activity.)

    For best groups I get them to make NaOH standard solutions of 0.25M and titrate against HCl using phenolphthalein as the indicator.

    Never had any problems using either.
     
  3. Hello sorry I forgot to say this is for the first A Level required practical! Posted in a bit of a rush!

    We want to titrate sodium hydroxide and sodium hydrogen sulfate, with the students making up their own solution of sodium hydrogen sulfate.

    The practical is tomorrow and i've just opened up the bottle to see that the sodium hydrogen sulfate is in huge lumps!
     
  4. Should be a moderately soluble salt like powder also known as sodium bisulfate. Where did you get it from?
     
  5. It says it's sodium hydrogen sulphate, and a powder is what I expected! It's in really big hard lumps instead. It was from better equipped.
     
  6. 007

    007 COMMITTEE

    Remember you can alter these practicals to suit your availability as long as the same skills are being carried out so I would use sodium carbonate instead. I had an OCR practical endorsement visit last year and they had no issues with me using sodium carbonate instead of the suggested chemical in their notes.
     
  7. Just had a quick look at better equipped - they spelt 'sulfate' with a 'ph' which is a bit worrying
    upload_2019-11-7_14-15-45.png
    You've got the fused form which is the only one they do but should be able to break it up with a mortar and pestle.

    Most other suppliers sell the powdered form
     
    Last edited: Nov 7, 2019
  8. Thank you both for your help!

    I'll try and break it up if not we'll go with the sodium carbonate.

    Phew panic over :)
     
  9. If it's difficult take the smallest pieces and put them is a strong bag hold the mouth closed and hit with a hammer - then finish off with pestle
     
  10. The whole point of the exercise is to standardise the Sodium Hydroxide with a Primary standard - Sodium Hydrogen Sulfate. Could also have used Sulfamic Acid. As for the dissolution, you could have ground down the lumps into powder then heated in an oven to make sure it's dry before weighing.