What may be the negative catalyst?

duke656

The reaction between sodium carbonate and calcium chloride gives the table salt and calcium carbonate. The reaction takes place immediately after mixing two solutions. Can anyone suggest me how the reaction can be slowed down?

Thank in advance
Peace
Deb

aroc91

The most obvious way is to lower the temperature.

chemisttree

The rate is limited by the diffusion and 'availibility' of materials in solution. You might try using a thickener in solution along with a sugar. Sugar complexes calcium and competes with the carbonate. Premix the sugar with the calcium chloride solution and then add thickener. Add thickener to the sodium carbonate solution and then briefly mix the two solutions.

duke656

Thank yo very much aroc91 and chemisttree. I once tried by lowering the temperature. It did not work actually, probably because I want to mix higher concentration say 0.5 molar solution. I will follow the suggestion of chemisttree and let you know. If you have other ideas please share with me.

Peace
Deb

duke656

Can you please suggest me what may be the probable thickeners? Is it sodium polyacrylate? or sodium alginate or gums.

Thanks in advance

Peace
Deb

morrobay

Pectin : A polysaccharide used in making jams , jellies. A thickener and suspending
agent. Look in a supermarket for this product.

chemisttree

Polyacrylate won't work. Calcium precipitates the polyacrylate. Calcium is a well known crosslinker for alginate as well so that won't do either. I was thinking of starches. Perhaps cornstarch. Thicken the starch in plain water and then add the calcium to test if it works.

chemisttree

Good idea. Pectin crosslinks with calcium so you can control the thickness AND chelate the calcium in one step... no sugar needs to be added. Make the pectin in plain water and add a solution of calcium to it. Allow it to sit a bit and then add the carbonate solution. Just might do it.

http://www.pomonapectin.com/faqs.html