Acids/Base

Acids Acids- form H + ions when dissolved. Strong acids fall apart completely.  many ions Weak acids- don’t dissociate completely. There are only seven strong acids: Hydrochloric (HCl) Hydrobromic (HBr) Hydroiodic (HI) Nitric (HNO 3 ) Sulfuric (H 2 SO 4 ) Chloric (HClO 3 ) Perchloric (HClO 4 )

Bases Arrhenius defined bases as substances that increase the concentration of OH − when dissolved in water. Brønsted and Lowry defined them as proton acceptors. The strong bases are the soluble metal salts of hydroxide ion: Alkali metals Calcium Strontium Barium

Acid - Base Reactions Acid donates a H+ ion to the base. Often called a neutralization reaction. Acid + Base  salt + water What is the net ionic equation for the reaction of HCl(aq) and KOH(aq)? H + + OH -  H 2 O

Gas Forming Reactions Some reactions can form a gas through a decomposition of one of the products. In this reaction, the expected product (H 2 CO 3 ) decomposes to give a gaseous product (CO 2 ): CaCO 3 (s) + HCl(aq)  CaCl 2 (aq) + CO 2 (g) + H 2 O(l) Similarly, when a sulfite reacts with an acid, the products are a salt, sulfur dioxide, and water: SrSO 3 (s) + 2HI(aq)  SrI 2 (aq) + SO 2 (g) + H 2 O(l)

Titration Solution of known concentration (titrant), Titrant is added to the unknown (analyte), This is done until the equivalence point is reached where enough titrant has been added to neutralize the analyte.

Titration Where the indicator changes color is the endpoint. Endpoint is not always at the equivalence point. A mL sample of aqueous Ca(OH) 2 requires mL of M Nitric acid for neutralization. What is [Ca(OH) 2 ]?

Acid-Base Reaction 75 mL of 0.25M HCl is mixed with 225 mL of M Ba(OH) 2. What is the concentration of the excess H + or OH - ?