Anonymous asked in Science & MathematicsChemistry · 7 months ago

How to identify an acid?

Like How do I know if HF is Hydrogen Fluoride or if its Hydrofluoric acid? And before some replies with the "AcIds have Hydrogen and bases have Hydroxide," No that doesn't help at all. H20 has hydrogen and isn't acid. But HI does have hydrogen and is acid. plus H2S04 could either be dihydrogen Sulfate or sulfuric acid, how do I identify? By chemical formula

2 Answers

  • 7 months ago
    Favorite Answer

    Identify an acid from what?

    The formula? Acids frequently start with "H", as in HCl, HNO3, H2SO4, H3PO4, or they may be organic acids with the -COOH group, as in HCOOH, CH3COOH, etc.

    Some acids can exist as molecules outside of water. HF, HCl, and HBr can be gases, but when these gases are dissolved in water they dissolve and ionize to form the acid solutions. Look for the state symbol. HF(g) is molecular hydrogen fluoride gas, while HF(aq) is hydrofluoric acid since it is dissolved in water.

    There is no "dihydrogen sulfate". The name of H2SO4 is sulfuric acid whether it is dissolved in water or not. That's because H2SO4 has acid properties regardless.

    Water is a special case since it is formed in acid/base neutralization reactions. Water, HOH comes from the cation of the acid and the anion of the base, just the reverse of a "salt."

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    • pisgahchemist
      Lv 7
      7 months agoReport

      No. H3PO4 is phosphoric acid. The prefix "hydro-" is reserved for binary compounds which are acids: HCl is hydrochloric acid, but HClO3 is chloric acid.

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  • david
    Lv 7
    7 months ago

    There are several different definitions of acids. HF can 'donate' a H+ in reactions so by one of those definitions it is an acid. Another definition is based on dissolving in water and releasing H+ ions, so, as a gas, it is not dissolved in water and is not an acid YET. ----Like words in the English language, sometimes the use determines the actual meaning if the word.

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