I have just bought some Caustic Soda to try and shift some awkward staining in the toilet bowl.Just curious why the label states "don't add water to the soda--add soda to the water"What's the differencw?
Thanks to you both--(I also read somewhere that caustic soda and vinegar shouldn't be mixed together as the mixture would create a lumpy mass)--Am I right in thinking this?
its the gas produced by mixing water and caustic soda. If you add the smaller amount of soda to the larger amount of water, it will bubble and therefore spit less and be safer...also any chemical reaction gives off heat and the heat will be instantly dissipated into the water. I was told at school that adding a small amount of water to a large amount of caustic soda can actually start a fire!
When Sodium Hydroxide (Caustic soda) and water are mixed the reaction produces a lot of heat. (an exothermic reaction) If you drop the Soda into water the water just warms up slightly. If you drop a little water onto the Soda the water gets so hot it boils almost instantly and spits boiling caustic which will cause a severe burn, if it gets into your eyes it can blind you!
Caustic soda is an alkali , vinegar is an acid. Mixing acid and alkali will cause an even more violent reaction than mixing alkali and water. Don't do it!
Woofgang a chemical reaction can be either exothermic which produces heat , or endothermic which absorbs heat and get colder!
Exotherms are more common. But a common endothermic reaction is to mix ice and common salt, the mixture gets cold. This is still used to produce a freezing mixture, you can even use it to make ice cream!
You put the ice cream mixture in a bowl , normally metal as it conducts heat faster, and put the bowl in the ice/salt freezing mixture.
By the way if the stain in the toilet is caused by hard water , lime scale it is useless to use caustic soda. You need an acid such a Hydrochloric acid or cola which has some Phosphoric acid in it. But the best answer is to use toilet lime scale remover . You can buy Hydrochloric acid, it is sold as 'Spirit of Salts' that is the best lime scale remover you can get.