Australia's Science Forum

Our Yr11Chem prac "Kinetic Theory in Action" requires NaHSO3 (sodium hydrogensulfite / sodium bisulfite), but this chemical is hard to find or not easy to order.

Can anyone tell me where they get their NaHSO3 from, or if you subsitute something else for it in the prac?

Annette.

Annette,

What's the prac? What do they want you to do with that?

Text book P273 Addison-Wesley: Chemistry, prentice hall, Matta etal, 2002.

Students generate different gases and use indicators to visualise gas diffusion. Different solutions are dropped on a petri dish in a patter and drops change colour as gas diffuses.

We also do a really cool experiment with a gas tube, overhead acetate and pH paper.

I cut a very long skinny strip of acetate, that fits into a gas tube or, even better, a gas tube or burette that has a broken end. Then I cut little slashes into the acetate at regular intervals, so that I could weave in little strips of pH paper. Feed the strip into the gas tube. At one end place a cotton ball soaked in ammonia, and at the other, a cotton ball soaked in conc acid (usually HCl or Acetic) and hold it level, parallel to the floor. Watch the pH strips change colour as the fumes migrate down the tube, and neutralize at the centre. Awesome!