No, you should add the soda crystals to a larger quantity of water. If you pour some water into a quantity of dry soda crystals, you can get an explosion from the exothermic reaction and gassing.Sounds like the Flake Sodium Hydroxide we used at work in the 60s-70s. Donot add to water but add the water to it. And as advised, use rubber gloves and eyewear when handling.
When the water hits it, it generates a lot of heat. It does clean car parts very well and is an excellent paint remover.
Also, beware putting dry crystals down into a pipe, it can set into a solid lump or possibly the reaction may blow the dangerous stuff out!
Usually, the soda should be mixed to a suitable solution and used as per the instructions.
Beware, this stuff is lethal to animals, children and even adults if safety precautions are not followed!
Cheers
Eng