Intro to Acids & Bases General Properties Indicators Neutralization Reactions

Acids A compound that produces hydronium ions (H 3 O + ) when dissolved in water – Ex: HCl + H 2 O → H 3 O + + Cl - Common Acids: Hydrochloric acid (HCl), Nitric Acid (HNO 3 ), Sulfuric Acid (H 2 SO 4 )

General Properties of Acids Sour Taste – Ex: Citric Acid (citrus fruits), Acetic Acid (vinegar) Reacts with metals – to produce H 2 gas Produces certain color changes in indicators – blue litmus → red

Bases A compound that produces hydroxide ions (OH - ) when dissolved in water – Ex: NaOH → Na + + OH - Common Bases: – Calcium Hydroxide Ca(OH) 2 ; Sodium Hydroxide NaOH; Magnesium Hydroxide Mg(OH) 2

General Properties of Bases Bitter Taste – Ex: Chocolate w/o sugar contains the base theobromine Slippery Feel (soap) Produces certain color changes in indicators – red litmus → blue

Indicators Any substance that will change colors based on different conditions, especially in the presence of acids or bases – Examples: litmus paper, phenolphthalein

pH Scale A scale from 0-14 that describes the concentration of hydronium ions (H 3 O + ) in a solution – Remember: H 3 O + ions are produced by acids when they dissolve in water The pH scale measures the “acidity” of a solution

pH Scale 7 Neutral 0-6 Acids 8-14 Bases

pH Values Lower pH values = more H3O+ ions – More acidic Higher pH values = less H3O+ ions – Less acidic (more basic)

pH Scale (w/examples) 7 Neutral 0-6 Acids 8-14 Bases

Neutralization Reactions Double Replacement reaction between an acid and a base The negative ions (anions) from the acid combine with the positive ions from the base (cations) to form an ionic compound called a salt Second product is water

Neutralization Reactions HCl + NaOH →  HCl + NaOH → HOH + NaCl HNO 3 + Mg(OH) 2 → ?  HNO 3 + Mg(OH) 2 → Mg(NO 3 ) 2 +H 2 O H 2 SO 4 + LiOH → ?  H 2 SO 4 + LiOH → Li 2 SO 4 + H 2 O