Common Acids and Bases Six Common Strong Acids Strong acids ionize 100% in water. Strong acids are strong electrolytes. Example: HCl( aq ) H + ( aq ) + Cl - ( aq ) Strong acids are strong electrolytes. Their solutions ocnduct electricity well.
18 Weak Acids Weak acids ionize very little in water. Weak acids are weak electrolytes. Weak acids mostly remain in their molecular form in water. Ex. HF in H 2 O remains mostly HF molecules Example: HF( aq ) H + ( aq ) + F - ( aq ) Weak acids: T heir solutions conduct electricity, but not well. Strong bases § A strong base produces hydroxide ions in solution for each formula unit of the original base. NaOH (s) → Na + (aq) + OH – (aq) § The common strong bases are the soluble hydroxide salts: group I hydroxides: LiOH, NaOH, and KOH group II hydroxides: Sr(OH) 2 and Ba(OH) 2 Strong bases dissociate 100% in water. They are strong electrolytes . Weak bases § A weak base is a molecular compound that reacts with water to produce OH - ions in solution but where the ionization is not complete. § Example: NH 3 NH 3 (g) + H 2 O( l ) ⇄ NH 4 + (aq) + OH – (aq) § Other example: Mg(OH) 2 , NaHCO 3 Weak bases only ionize a small percent in water. They mostly remain in the form of molecules. They are weak electrolytes.
19 Learning check: Which of the following is a weak base? a) HClO 4 b) H 2 CO 3 c) LiOH d) NH 3 e) KBr f) HF Learning check: which of the following is a weak electrolyte?* A. NaCl B. KOH C. HF D. Sugar molecules E. HClO 4 Acid - Base Neutralization General reaction Acid + Base Salt + Water HCl + NaOH NaCl + H 2 O a type of metathesis reaction HCl + NaOH NaCl + HOH • Write the net ionic equation
20 K + (aq) + Br – (aq) Strong acid - Strong base neutralization: HBr(aq)/KOH(aq) Molecular Equation: Total Ionic Equation: HBr(aq) + KOH(aq) KBr (aq) + H 2 O( l ) H + (aq) + Br – (aq)+ K + (aq) + OH – (aq) + H 2 O( l ) Net Ionic equation: H + (aq)+ OH – (aq) H 2 O ( l ) / / / / Reactions of Acids & Bases: Acid-Base Neutralization This applies to ALL reactions of STRONG acids and bases. What is the net ionic equation for the reaction between HClO 4 and KOH? A. HClO 4 + KOH KClO 4 + H 2 O B. H + + OH H 2 O C. HClO 4 + OH ClO 4 + H 2 O D. H + + KOH H 2 O + K + Total Ionic Equation: Reactions of weak acids and strong bases: Molecular Equation: HC 2 H 3 O 2 (aq) + NaOH(aq) NaC 2 H 3 O 2 (aq) + H 2 O( l ) HC 2 H 3 O 2 (aq) + Na + (aq) + OH – (aq) Na + (aq) + C 2 H 3 O 2 – (aq) + H 2 O( l ) Leave in molecular form Net Ionic: HC 2 H 3 O 2 (aq) + OH – (aq) C 2 H 3 O 2 – (aq) + H 2 O( l ) / / Reactions of Acids & Bases: Acid-Base Neutralization
21 Metal carbonate salts react with acids to the corresponding metal salt, water and carbon dioxide gas. 2HCl(aq) + CaCO 3 (s) CaCl 2 (aq) + H 2 CO 3 (aq) H 2 O( l ) + CO 2 (g) Decomposes to Similarly: NaCl(aq) + H 2 O( l ) + CO 2 (g) HCl(aq) + NaHCO 3 (s) acid base salt water Neutralization!!!
- Fall '19