Drain cleaner

https://en.wikipedia.org/wiki/Drain_cleaner 

A drain cleaner is a chemical-based consumer product that unblocks sewer pipes or helps to prevent the occurrence of clogged drains. The term may also refer to the individual who uses performs the activity with chemical drain cleaners or devices known as plumber's snake. Drain cleaners can be classified in two categories: chemical, or device.

Chemical drain cleaners can be in solid or liquid form that are readily available through hardware stores, though some (primarily acidic ones) are intended for use by licensed plumbers.[1]

Alkaline drain cleaners are available in either solid or liquid state while the acidic ones are usually in liquid form.

Alkaline drain openers primarily contain sodium hydroxide (lye) and some may contain potassium hydroxide. They may appear in liquid or solid form.

Solid formulations of corrosive alkaline drain cleaners are composed of a caustic substance (often sodium hydroxide or potassium hydroxide), aluminum particles, and 'additives.' These additives often include wetting agents such as alkyl aryl sulfonates, but the exact nature of these additives are not known for commercial drain cleaners, as they are regarded as the trade secrets that make each drain cleaner unique to its brand.

The aluminum granules that are included in the solid caustic drain cleaner is an aluminum oxide that breaks down and re-oxidizes to release hydrogen gas. The components of this reaction are shown below. Because the release of hydrogen gas is overall an exothermic reaction, the extra heat released helps to break down the greases, oils, etc. that form the clog.

1. Breakdown of Aluminum Oxide: Al2O3 + 2NaOH + 3H2O ---> 2Na [Al(OH)4]

2. Oxidation of Aluminum metal: 2Al + 2NaOH + 6H2O ---> 2Na[Al(OH)4] + 3H2

Acid drain cleaners usually contain sulfuric acid at high concentrations.[3] It can dissolve cellulose, proteins like hair, and fats via acid hydrolysis.

According to a manufacturer, potential hazards include violent reaction with water and the production of explosivehydrogen vapors upon contact with most metals; chronic (delayed) and acute (immediate) health hazards if inhaled, ingested, or contacted, including severe eye, flesh and skin burns or even permanent visual loss, inflammation of respiratory membranes, and corrosive burns to all human tissue. It may even be fatal if swallowed.[4] Due to the vigorous reaction between the acid and water, such acidic drain openers should be added slowly into the pipe to be cleaned.