[bakedpotato]

Hi,

I have a project where I have to develop reversal film and the process calls for a bleach solution based on potassium dichromate.
I am trying to figure out how to convert a recipe that uses potassium dichromate crystals. Potassium dichromate is very toxic and I would prefer to manipulate the chemical in a liquid state.

The chemical recipe calls for

1200ml  distilled water
70ml     50% Sulfuric Acid
15g      potassium dichromate crystals
           water to make 1500ml

The available potassium dichromate solution concentrations are:

product#1: 0.1000N ±0.0005N (0.0167M)
and
product#2: 0.200N ±0.001N (0.0333M)

How can I find how much solution(ml) of each of the K dichromate products I will need to make it equivalent to 15g of crystals diluted in ~1430ml of distilled water and 70 ml of acid.

I need to end up with 1,5L of total solution as this is the min size of the bath and maximum size of the storage container.

Any help is welcome!

Thanyou

[Borek]

Potassium dichromate is very toxic and I would prefer to manipulate the chemical in a liquid state.

While it is definitely toxic, don't panic. I worked with the dichromate in the past. With a minimum precautions and in the case of a single use (ie you will be not working with it on a daily basis for months) it is quite safe. Use gloves, avoid breathing the dust - and it is not a a substance that has tendency to become airborne, just don't throw it in the air. In the case of this particular recipe I would be more careful when measuring and adding the 50% sulfuric acid.

Solutions you have listed

product#1: 0.1000N ±0.0005N (0.0167M)
and
product#2: 0.200N ±0.001N (0.0333M)

are probably quite expensive compared to the solid, as preparing solutions of precisely known concentrations is labor expensive.

That being said - it is a simple dilution, so calculations are rather easy. Just calculate what volume of the available solutions contain 15 g of dichromate, following the usual path - mass -> moles -> volume.

[bakedpotato]

Thanks for your response Borek.

I will use the crystals as they are cheaper and will take every precaution while manipulating the chemicals.

[Borek]

Don't get crazy about it - common sense is all you need. Apron, glasses, gloves and working under fume hood (or in open) are perfectly enough.