Bottled muriatic acid is 37% HCl… this is the highest concentration that hydrogen chloride acid gas will dissolve in water… it’s NOT dilute at all.. must handled with caution, especially with fumes. It’s available in hardware store to etch concrete. I use it clean toilet bowls with hardwater rings- poured directly into the water and scrubbed with a plastic brush, it removes hard water rings instantly, sterilizes the bowl, removes all traces of soil and fecal matter. I can’t just flush it down without first neutralzing it with washing soda. The acid will eat up old iron sewer pipes. Keep on adding more washing soda until all the fizzing stops. Even at that, the result is SALT.. salt is also corrosive for old iron pipes. flush three times to wash the salt out of the system…using a brush with plastic scrubber and metal spiral fastner for the bristles turns the fastner into rust very quickly..Muriatic acid must be handled with precautions. It’s dangerous. Not as dangerous as nitric, but still very dangerous nonetheless..Always be careful when using it- concentrated or diluted, it’s still very corrosive! Your advice to always add acid to water is well taken. Don’t even add water to acid. Concentrated sulfuric acid and anhydrous acetic acid (glacial acetic acid), both have violent reactions when water is added to them and not vice versa.
And the fumes will destroy/corrode any exposed metal inside or outside the house if it is opened for a prolonged period of time.
Anything stronger than azeotrope (21%) will create fumes, more as stronger it gets.
Nitric acid gas is even worse. Fumes from nitric acid is nitric acid, Nitrogen dioxide, the brown fumes when nitric acid eats away metal is also an strong oxidant, it too will cause burn and lung damage if inhaled. It will also corrode metal itself.
No one should even think about using Hydrofluoric acid in the first place. HFl is extreme corrosive, etches away glass, silicate stones, quartz. That’s it only purpose - to etch glass and silicates…Neutralizing with it baking soda, still causes it to burn skin and flesh. The Fluoride ion is toxic. high concentrations kill cells. A true medical emergency- the only way to stop it from burning is to precipitate it with soluble calcium gluconate. Calcium binds fluoride as calcium fluoride, the insoluble mineral fluorite.
HF is probably the worst one can come in contact with. It can/are used for devesting some investments, but has been replaced by NaOH/KOH which are also bad for skin and eyes.
Sodium Hydroxide and Potassium Hydroxide is LYE.. it’s much safer than HF, but still is caustic lye, causes bad burns if handled improperly. The strength of an acid of alkali dependent on how much of it dissociates into ions in an aqueous solution. The pKa of an acid or alkali doesn’t necessarily correlate to its corrosiveness. Oxidizing acids, like HNO3 and Oxalic acid are more corrosive to metals than acids that are non oxidizing, like HCl. Organic materials like skin and flesh are more completely destroyed by strong alkalis.
You do not want to mess with HydroFloric acid. That is what HF is.