Inorganic chemistry Assistance Lecturer Amjad Ahmed Jumaa  Arrhenius theory of acids and bases.  Arrhenius acids.  Arrhenius bases. 1

 Acids and Bases: Savante Arrhenius (1884) proposed his concept of acids and bases.  Arrhenius theory of acids and bases:  Arrhenius acids: An acid is a substance that when dissolved in water, releases (H + ), or (increase the concentration of hydronium ion, H3O + (aq)). For example: HCl is an Arrhenius acid.  Acids and Bases: Savante Arrhenius (1884) proposed his concept of acids and bases.  Arrhenius theory of acids and bases:  Arrhenius acids: An acid is a substance that when dissolved in water, releases (H + ), or (increase the concentration of hydronium ion, H3O + (aq)). For example: HCl is an Arrhenius acid.

3  Arrhenius bases: A base is a substance when dissolved in water, release (OH - ), ions, or (increase the concentration of hydroxide ion, OH - (aq)).  Arrhenius bases: A base is a substance when dissolved in water, release (OH - ), ions, or (increase the concentration of hydroxide ion, OH - (aq)). HCl (aq) H + (aq) + Cl - (aq).

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NaOH(aq) OH - (aq) + Na + (aq). Arrhenius acids: Were generally recognized as a substance that in aqueous solution, would: 1- Taste sour when diluted enough to be tasted. 2- Cause litmus paper to change from blue to red. 3- React with active metals such as magnesium, zinc, and iron to produce hydrogen gas, H 2 (g): For example: Hydrochloric acid HCl (aq),(Arrhenius acid), react with magnesium metal to produce hydrogen gas and magnesium chloride: Arrhenius acids: Were generally recognized as a substance that in aqueous solution, would: 1- Taste sour when diluted enough to be tasted. 2- Cause litmus paper to change from blue to red. 3- React with active metals such as magnesium, zinc, and iron to produce hydrogen gas, H 2 (g): For example: Hydrochloric acid HCl (aq),(Arrhenius acid), react with magnesium metal to produce hydrogen gas and magnesium chloride:

2HCl (aq) + Mg(s) → H 2 (g) + MgCl 2 (aq). 4- React with bases (they contain hydroxide ion, OH - ), to form water and compounds called salts. For example: hydrochloric acid, HCl (aq), react with potassium hydroxide, KOH (aq) as a base, to form water and potassium chloride (salt). 4- React with bases (they contain hydroxide ion, OH - ), to form water and compounds called salts. For example: hydrochloric acid, HCl (aq), react with potassium hydroxide, KOH (aq) as a base, to form water and potassium chloride (salt). HCl (aq) +KOH (aq) → H 2 O + KCl(aq). Acid base salt. HCl (aq) +KOH (aq) → H 2 O + KCl(aq). Acid base salt. Salts: is formed (is made up) of the cation from the base and the anion from the acid. The reaction of an acid with a base called neutralization. Salts: is formed (is made up) of the cation from the base and the anion from the acid. The reaction of an acid with a base called neutralization.

 Neutralization: If the correct amounts of acids and bases are mixed together, the original properties of the acid and bases are lost. The reaction product has a taste that is salty sour or bitter. A salt and water were formed when an acid neutralizes a base. For example:  Neutralization: If the correct amounts of acids and bases are mixed together, the original properties of the acid and bases are lost. The reaction product has a taste that is salty sour or bitter. A salt and water were formed when an acid neutralizes a base. For example: H 2 SO 4 (aq) + 2KOH (aq) → 2H 2 O ( l ) +K 2 SO 4 (aq). Acid base salt. H 2 SO 4 (aq) + 2KOH (aq) → 2H 2 O ( l ) +K 2 SO 4 (aq). Acid base salt.

9 1-Taste bitter (chemical used in the laboratory should never be tasted. 2- Feel slippery or soapy on the skin 1-Taste bitter (chemical used in the laboratory should never be tasted. 2- Feel slippery or soapy on the skin  Arrhenius bases: (also called alkalies), were generally recognized by Arrhenius as that substance that in aqueous solution would:  Arrhenius bases: (also called alkalies), were generally recognized by Arrhenius as that substance that in aqueous solution would:

3- Cause red litmus to change from red to blue. 4- React with acids to form water and salts. NaOH (aq) + HBr(aq) → H 2 O( l ) + NaBr(aq). And thus: if you want to know wither a given compound, is an Arrhenius acid or base, just dissolve some of it in pure water and put a drop or two of the solution on blue litmus paper: If the litmus turns red, the compound is an acid, however if the solution turns red litmus to blue, the presence of a base compound is indicated.

 Many foods are acidic, cider vinegar contains acetic acid, lemons and other citrus fruits as well as many fruit- flavored drinks contain citric acid.