Acid-Base Reactions SNC2D

pH Scale We use this scale to measure the strength of an acid or base. pH refers to the power of Hydrogen. pH is defined as the –log [H+], a logarithmic scale A change of 1 on the scale means a 10x increase in H+ concentration A pH of 5 is 10x more acidic than a pH of 6

Neutralization The reaction between an acid and a base produces water (H2O) and an ionic compound known as a salt, which may be dissolved in the water or form as a precipitate.

Neutralization The reaction between an acid and a base produces water (H2O) and an ionic compound known as a salt, which may be dissolved in the water or form as a precipitate. Example hydrochloric acid + sodium hydroxide 

Neutralization The reaction between an acid and a base produces water (H2O) and an ionic compound known as a salt, which may be dissolved in the water or form as a precipitate. Example hydrochloric acid + sodium hydroxide  water + sodium chloride

Neutralization The reaction between an acid and a base produces water (H2O) and an ionic compound known as a salt, which may be dissolved in the water or form as a precipitate. Example hydrochloric acid + sodium hydroxide  water + sodium chloride HCl(aq) + NaOH(aq) H2O(l) + NaCl(aq)

Neutralization This ________________ reaction is also known as a ___________ because the products of the reaction are neutral (i.e. have a pH of ?).

Neutralization This double displacement reaction is also known as a ___________ because the products of the reaction are neutral (i.e. have a pH of ?).

Neutralization This double displacement reaction is also known as a neutralization because the products of the reaction are neutral (i.e. have a pH of ?).

Neutralization This double displacement reaction is also known as a neutralization because the products of the reaction are neutral (i.e. have a pH of 7).

Neutralization This double displacement reaction is also known as a neutralization because the products of the reaction are neutral (i.e. have a pH of 7). Another Example sulphuric acid + potassium hydroxide 

Neutralization This double displacement reaction is also known as a neutralization because the products of the reaction are neutral (i.e. have a pH of 7). Another Example sulphuric acid + potassium hydroxide  water + potassium sulphate

Neutralization This double displacement reaction is also known as a neutralization because the products of the reaction are neutral (i.e. have a pH of 7). Another Example sulphuric acid + potassium hydroxide  water + potassium sulphate H2SO4(aq) + KOH(aq)  H2O(l) + K2SO4(aq)

Neutralization This double displacement reaction is also known as a neutralization because the products of the reaction are neutral (i.e. have a pH of 7). Another Example sulphuric acid + potassium hydroxide  water + potassium sulphate H2SO4(aq) + 2 KOH(aq)  2 H2O(l) + K2SO4(aq)

Neutralization Some neutralization reactions will also produce carbon dioxide. Example hydrochloric acid + sodium bicarbonate  water + sodium chloride + carbon dioxide HCl + NaHCO3  H2O + NaCl + CO2

Neutralisation Reactions Review Reaction between an acid and a base Is a double displacement reaction Acid + Base  Salt + Water A salt is an ionic compound produced by the reaction of an acid or a base.

Example: e.g.HBr(aq) + NaOH(aq)  NaBr + H2O salt Many different acids and bases mean many different salts.  

Uses Neutralization reactions are useful on small scales, e.g. the formic acid (HCOOH) in a beesting that attacks nerves in the skin can be neutralized with an ammonia-based cream

Uses and on large scales, e.g. lime may be added to an acidified lake to raise its pH: HNO3 + Ca(OH)2 

Uses and on large scales, e.g. lime may be added to an acidified lake to raise its pH: HNO3 + Ca(OH)2  Ca(NO3)2 + H2O

Uses and on large scales, e.g. lime may be added to an acidified lake to raise its pH: 2 HNO3 + Ca(OH)2  Ca(NO3)2 + 2 H2O

Key Concepts: Acids and Bases Acids and Bases Acid Base Ionization in water undergo produce produce Neutralization gives H + ions OH- ions to form OH- H+ 100% Small % Salt & 100% Small % product Water [H+] x [OH-] Strong acid Weak acid Strong base Weak base is pH