Australia's Science Forum

A teacher who has since moved on, entered this under Elephant Toothpaste on RiskAssess:

100mL 30% hydrogen peroxide
saturated potassium hydroxide solution
1 x 500mL measuring cylinder
dishwashing detergent

I signed off after adding the following under Control Measures:

using KI (not KOH) as per procedure reference
Additional measures: safety glasses, gloves

RiskAssess assessed KI but not the sat'd KOH as requested under 'Items to be prepared by lab tech' and another teacher has since re-ordered this prac. So what happens should a newbie innocently prepares the 'Teacher only' chemical as requested, with potentially disastrous consequences?

What is the KOH used for in this exp? Is it the catalyst? I've only used yeast or KI in this.

Can you (or the new teacher) make a new risk assess order with KI instead of KOH?

Can you do an authors update on the risk assessment and just delete the saturated KOH and replace it with KI? If the assessment is set because of the signature then make a modifiable copy and then make the adjustment. Then delete the original assessment. Only problem after that is that the original is held in a deleted file and I don't know if that can be removed completely so that no mishaps can occur with new labbies. Just give it a try if you have concerns.

Done. Thanks Lyn.