phosphorous acid

American  

noun

Chemistry.

1. a colorless, crystalline, water-soluble acid of phosphorus, H 3 PO 3 , from which phosphites are derived.

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phosphorous acid British  

noun

1. Systematic name: phosphoric acid.  Also called: orthophosphorous acid.  a white or yellowish hygroscopic crystalline dibasic acid. Formula: H 3 PO 3

2. any oxyacid of phosphorus containing less oxygen than the corresponding phosphoric acid

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phosphorous acid Scientific  

/ fŏs′fər-əs,fŏs-fôr′əs /

1. A white or yellowish crystalline solid used as a reducing agent. It is hygroscopic (easily absorbs moisture from the atmosphere). Chemical formula: H ₃ PO ₃ .

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Etymology

Origin of phosphorous acid

First recorded in 1785–95

Example Sentences

Like most other nonmetal halides, both phosphorus chlorides react with an excess of water and yield hydrogen chloride and an oxyacid: PCl3 yields phosphorous acid H3PO3 and PCl5 yields phosphoric acid, H3PO4.

From Textbooks • Feb. 14, 2019

Write equations showing the stepwise ionization of phosphorous acid.

From Textbooks • Feb. 14, 2019

When sufficient water evaporates, white crystals of phosphorous acid will appear upon cooling.

From Textbooks • Feb. 14, 2019

The best method for preparing pure phosphorous acid is by hydrolyzing phosphorus trichloride:

From Textbooks • Feb. 14, 2019

The white fumes of phosphorous acid floated out into the air, and began to diffuse themselves through the hall towards the ventilation outlets at the sides and rear.

From Peter Cooper The Riverside Biographical Series, Number 4 by Raymond, Rossiter W. (Rossiter Worthington)