98 Sulfuric Acid

98% sulfuric acid (also called concentrated sulfuric acid or “oil of vitriol”) is a highly corrosive, strong mineral acid with the formula H₂SO₄. It is the most common commercial form of sulfuric acid, typically 95–98% by weight (often labeled as 98% or 96–98%).

Key Physical and Chemical Properties

Appearance: Colorless to slightly yellow, oily, viscous liquid (odorless when pure).
Density: Approximately 1.84 g/cm³ (or 1.83–1.84 g/mL) at 20°C.
Molarity: Roughly 18 M (molar) for 95–98% concentration. This makes it one of the strongest and most concentrated acids used in labs and industry.
Boiling point: Around 290–338°C (varies slightly with exact concentration); it decomposes before fully boiling in higher purities.
Molecular weight: 98.08 g/mol.
Behavior with water: Highly hygroscopic (absorbs moisture from air) and releases a large amount of heat when diluted (exothermic reaction). Always add acid to water slowly with stirring—never add water to acid, as it can cause violent splashing or boiling.

It acts as a powerful dehydrating agent, oxidizer, and strong acid. It can char organic materials (like wood, sugar, or paper) by removing water from them and is highly reactive with many substances, including metals (producing hydrogen gas) and bases.

Common Uses

98% sulfuric acid is a critical industrial chemical used in:

Fertilizer production (e.g., superphosphate).
Petroleum refining, chemical manufacturing, dyes, and explosives.
Battery acid (though often diluted for lead-acid batteries).
Metal processing, etching, steel production, and laboratory reagents (ACS grade for analysis).

It is one of the most widely produced chemicals globally due to its versatility.

Safety and Hazards

98% sulfuric acid is extremely dangerous:

Corrosive: Causes severe chemical burns to skin, eyes, and respiratory tract on contact. It can cause permanent eye damage or blindness.
Inhalation: Fumes or mists irritate or damage lungs; long-term exposure to mists is carcinogenic.
Reactivity: Reacts violently with water, organic materials, metals, and bases. It is corrosive to many metals.
Other risks: May be corrosive to metals (GHS H290), causes severe skin burns and eye damage (H314/H318), and can release toxic sulfur oxides if heated.

Handling precautions:

Use in a fume hood or well-ventilated area.
Wear full PPE: chemical-resistant gloves, goggles/face shield, lab coat or apron, and boots.
Have neutralizing agents (like sodium bicarbonate) and emergency eyewash/shower nearby.
Store in compatible containers (glass or certain plastics) away from water, organics, and incompatibles.
In case of spill: Neutralize carefully and avoid direct water application initially.

First aid: Immediate rinsing with large amounts of water for skin/eyes (at least 15–20 minutes), remove contaminated clothing, and seek emergency medical help. Do not induce vomiting if swallowed.

For detailed safety information, always consult the specific Safety Data Sheet (SDS) from your supplier, as formulations can vary slightly.

Availability

It is sold as a laboratory reagent (ACS grade), technical/industrial grade, or in bulk. Suppliers include chemical companies like Sigma-Aldrich, Honeywell, or industrial distributors. In many places, purchases of concentrated acids are regulated or require permits due to safety and potential misuse concerns.

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Important note: This is a hazardous substance. Proper training, equipment, and regulatory compliance are required for any use. Do not attempt home experiments with concentrated sulfuric acid without expert knowledge and safety measures.