Reagent Bottle (Narrow Mouth), Plastic

Quick Answer: A plastic narrow mouth reagent bottle is a moulded bottle with a small neck and closure, used to store liquid reagents and pour them in a controlled stream. It does not shatter if dropped, which makes it popular for student reagent sets.

A Narrow Neck for Liquids

Liquids are easier to pour neatly from a small opening, and a narrow neck also exposes less surface to the air, slowing evaporation and the uptake of carbon dioxide or moisture. That is why narrow mouth bottles are the standard container for bench reagents such as dilute acids, alkalis, salt solutions and indicators, while wide mouth bottles are kept for solids.

The title says plastic without naming the resin. Most plastic reagent bottles are high-density polyethylene (HDPE), which is tough and resists dilute acids and alkalis but is generally not autoclavable, or polypropylene (PP), which is stiffer and generally autoclavable at 121 °C. Sodium hydroxide solution, which slowly etches glass and can make glass stoppers stick, is often better kept in plastic than in glass.

The glass narrow mouth reagent bottle remains preferable for organic solvents and for reagents that permeate plastics. For powders and crystals, use the matching wide mouth plastic bottle.

Applications

• Bench reagent sets of dilute hydrochloric acid, sodium hydroxide and salt solutions for student practicals
• Storing sodium or potassium hydroxide solutions, which attack glass over time
• Keeping distilled water or a buffer at a workstation
• Carrying reagents for field tests on water or soil, where glass is a breakage risk

Care & Handling

• Label each bottle with the reagent name, concentration and date before filling.
• Keep strong oxidising acids and organic solvents out of plastic bottles unless the resin is known to resist them.
• Wipe drips from the neck and threads before closing, so crystals do not form and jam the closure.
• Store out of direct sunlight; ultraviolet light weakens most plastics over time.

Specifications

Why Choose LabEquip

School and college labs issuing reagent sets to every bench want bottles that survive knocks and daily handling. LabEquip supplies plastic and glass reagent bottles in its chemistry lab equipment range; send capacities and quantities through the contact page.

Frequently Asked Questions

When should I choose a narrow mouth bottle instead of a wide mouth one?

Use narrow mouth bottles for liquids, which pour more neatly and evaporate less through a small opening. Wide mouth bottles are for solids and viscous materials that must be scooped or spooned out.

Is a plastic bottle suitable for sodium hydroxide solution?

Yes, and it is often preferred. Concentrated alkali slowly attacks glass and can cement a glass stopper in place, whereas polyethylene and polypropylene resist alkali solutions well.

Can organic solvents be stored in plastic reagent bottles?

Only if the resin is known to resist them. Many solvents, including chlorinated and aromatic ones, soften polyethylene or diffuse through it. Glass bottles are the usual choice for solvents.

Is the bottle autoclavable?

Polypropylene bottles generally tolerate autoclaving at 121 °C with the cap loosened, but HDPE bottles generally do not. Confirm the resin before sterilising.

Why do caps on reagent bottles stick?

Liquid dries on the threads and leaves crystals or a film that binds the cap. Wiping the neck before closing, and rinsing the threads occasionally, prevents most stuck caps.

How long can reagents be kept in a plastic bottle?

That depends on the reagent rather than the bottle. Stable salt solutions keep for months, while starch indicator or dilute hydrogen peroxide deteriorate within days or weeks. Date every label and remake reagents that change in appearance.

Last Updated: September 2026